REVIEW/TUTORIAL FOR THE COLLEGE ALGEBRA PLACEMENT TEST
 
1. Evaluate – x2 3x + 9 for x = 1
2.
Multiply and simplify:
3. Simplify and factor: 5x– 2(y – x) x
4.
Simplify:
5.
Simplify and write as a single fraction:
6.
Simplify as much as possible:
7.
Simplify by rationalizing the denominator:
 
8. Multiply: (8x3 y)(–3x2y7)
 
9. Find the slope of the line: 2x – 3y + 10 = 0
10.
Write as a single fraction in terms of
11.
Solve for all values of x:
12.
Solve for all values of x: = 5
13.
Multiply and simplify:
14. Find the solution set for x: 2x + 1 > 3x + 7
15. Solve for x: 2x2 + 3x – 2 = 0
16. Solve for x: 2x2 – 3x – 4 = 0
17. Solve for x: 2x2 – 6x + 5 = 0
18.
Evaluate:
19.
Solve for x and y:
20.
Find the solution set for x:
21.
Write as a single fraction.
22. Factor completely: x4 – 81.
23.
Add and simplify:
24. The graphs of the system of equation consists of lines that
a) intersect b) meet in one point c) are parallel
25.
Simplify:
26. Find the solution set for x: x2 + 6 > 5x
27. If f(x) = x3 + 1, find f(3)
28. Graph: y = 1
29. Graph: x = – 3
30. Graph: 2x + 3y = 2

     
 
ANSWERS FOR THE REVIEW/TUTORIAL
     
1. Answer 5
Evaluate – x2 3x + 9  for x = 1
When substituting x = 1 in   – x2
be sure to do the exponent before the multiplication by   1
    to get   (1)2 = 1.   So     1 3 + 9 = 5
 
2. Answer
When multiplying so that
   
becomes
 
3. Answer 2(3x - y)   
    Using the distribute law -2(y - x) = -2y + 2x we get:
5x– 2(y – x) x
= 5x– 2y + 2x– x
= 6x -2y
= 2(3x - y)
 
4. Answer
To divide by 3, we invert and multiply
 
5. Answer
Write the numerator as a single fraction with denominator of 4,
    and write the denominator as a single fraction with denominator of 6,
   
   
Now divide by
Be sure to invert and multiply to get
   
Here we divided the denominator 4 and the numerator 6 by 2.
 
6. Answer
  , 
     
since x4 is positive. Similarly
 
7. Answer
Since we write
   
 
8. Answer 24x5y8
When multiplying exponent expressions with the same base, keep the
    base and add the exponents thus, x3(x2) = x5 and y(y7) = y8
 
9. Answer
Write the equation of the line in the form y = mx + b or where m is the slope.
    3y = 2x 10
 
10. Answer
Write
and rationalize
Now we are adding
 
11. Answer
Multiply both sides of the equation by the denominator x – 3
   
Use the fact that
1 – 3(x – 3) = x
1 – 3x + 9 = x
10 = 4x
 
12. Answer x = – 5,   x = 5
There are two values of x whose absolute value is 5
|-5| = 5   and   |5| = 5
     
 
13. Answer
We factor x2 – 3x = x(x– 3)   and   9 – x2 = (3 – x)(3 + x)
Remember the difference of squares factorization
a2b2 = (ab)(a + b).
    Thus we get
Use the fact that x – 3 = – (3 – x),   so that
   
Putting this together we get
   
 
     
14. Answer x < – 6
2x + 1 > 3x + 7
Subtract 3x  from both sides – x + 1 > 7
Subtract 1 from both sides – x > 6
Multiply by – 1, we get x < – 6
Remember multiplying an inequality by a minus changes the sense of the arrow.
     
15. Answer
and x = – 2
Consider the standard quadratic equation ax2 + bx + c = 0,
whose solution is
For the solution of 2x2 + 3x – 2 = 0, a = 2, b = 3, and c = – 2.
Since the discriminant b2 – 4ac = 32 – 4(2)( –2) = 9 + 16 = 25 is a
perfect square, we can factor directly: 2x2 + 3x – 2 = 0,
(2x – 1)(x + 2) = 0
2x – 1 = 0 x + 2 = 0
x = – 2
     
16. Answer
For the solution of 2x2 – 3x – 4 = 0, we have a = 2, b = – 3, c = – 4.
The discriminant b24ac = (– 3)2 – 4(2)( – 4) = 9 + 32 = 41 is not a
perfect square so that we must use the quadratic formula and get
two real roots: Thus
     
17. Answer
For the solution of 2x2 – 6x + 5 = 0, a = 2, b = – 6, c = 5
     
The discriminant b24ac = (– 6)2 – 4(2)( 5) = 36 – 40 = – 4.
     
Since the discriminant is negative, the two roots are imaginary.
     
     
   
 
     
Thus, here we use
     
We can reduce the answer by factoring 2 in the numerator
     
     
18. Answer
The negative exponent means we have to take the reciprocal of what is in
the parentheses and then square.
Remember when raising a fraction to a power, both the denominator and
numerator are raised to that power
     
19. Answer x = 3, y = 2 Solve for x and y there are two methods that are often used.
Addition method: Multiply the second equation by – 5
     
5x – 3y = 21
– 5x – 25y = 35
Add the equations to get:
– 28y = 56
     
Substitute back into the second equation to get:
x + 5(– 2) = – 7
x – 10 = – 7
x = –7 + 10 = 3
Thus x = 3, y = 2.
     
Substitution method: Solve for x in the second equation to get:
x = –7 – 5y
Substitute for x in the first equation to get:
   
  5(–7 – 5y) – 3y = 21
  –35 – 25y – 3y = 21
  –35 – 28y = 21
Add 35 – 28y = 21 + 35
  – 28y = 56
  Divide by – 28
 
Substitute in equation two to get x. Substitute the value y = – 2
in x = – 7– 5y to get x = –7– 5(–2) = – 7 + 10 = 3
Thus x = 3, y = 2.
     
 
20. Answer Answer: 3 < x < 7
We can do the problem algebraically or geometrically.
Algebraically:
|x - 2| < 5 means –5 < x– 2 < 5
So by adding to 2 all three parts of the inequality we get
–5 < x –2 < 5
–5 + 2 < x –2 + 2 < 5 + 2
–3 < x < 7
     
Geometrically:
|x - 2| < 5 means that the distance (in both directions) from x to 2 is less than 5.
So if we move 5 units to the right (up the axis) from 2 we get 7 and 5 units
to the left (down the axis) from 2 we get –3
     
 
21. Answer
The least common denominator is xy. Thus
Since the denominators of the two fractions are now the same,
we can add the numerators getting
     
     
22. Answer (x – 3)(x +3)(x2 + 9)
Recall the factorization of the difference of squares a2 b2 = (ab)(a + b)
x4 – 81 is a difference of squares namely (x2 )2 and 92.
x4 – 81 = (x2 – 9)( x2 + 9). The first factor is again a difference of squares:
(x2 – 9) = (x – 3)(x +3)
x4 – 81 = (x2 – 9)( x2 + 9) = (x – 3)(x +3)(x2 + 9)
x2 + 9, the sum of squares, does not factor
     
 
23. Answer
The least common denominator is 24y.
Thus
Here since the denominators are the same we add the numerator.
     
 
24. Answer The lines are parallel.
If you solve for y in each equation to get the form y = mx + b,
you can examine the slopes m and the y intercepts b.
Equation 1 becomes:
Equation 2 becomes:
which reduces to
   
Since the slopes are equal and the y intercepts are not, the lines are
parallel. In the case that both the slopes and the y intercepts were equal,
    the lines would be the same.
    In the case that the slopes are unequal, the lines intersect in one point.
     
 
25. Answer 2
Think of as as
     
is the cube root of 8 often written as
     
   
So that
     
the meaning of a negative exponent.
     
   
is the square root of 4
     
often written Thus
     
 
26. Answer x < 2  or  x > 3
x2– 5x + 6 > 0
To find the solution set for x set the inequality equal to zero and factor and solve for x:
x2– 5x + 6 = 0
(x – 3)(x – 2) = 0
x = 3, x = 2
Since the inequality is strictly greater than zero, neither of these are in the solution set.
These two numbers divide the x axis into three sections:
     
¥ < x < 2, 2 < x < 3, and 3 < x < ¥
     
Pick any "test" number for each section and substitute into the inequality:
     
For – ¥ < x < 2, say x = 0.
     
Substituting x = 0 into x2– 5x + 6 gives us (0)2 – 5(0) + 6 = 6
    which is greater than zero.
     
Thus – ¥ < x < 2 is part of the solution set.
For 2 < x < 3, we can test with or
   
Substituting into x2– 5x + 6  gives us
which is less than zero.
     
Thus 2 < x < 3, is NOT in our solution set.
For 3 < x < ¥, we can substitute x = 4   to get
    42 – 5(4) +6 = 16 – 20 + 6 = 12 > 0.
Thus 3 < x < ¥ is part of the solution set.
Thus the complete solution set is {x| – ¥ < x < 2 or 3 < x < ¥}
which can also be written in interval notation as (– ¥, 2) (3, ¥).
     
27. Answer 28
If f(x) = x3 + 1, f(3) = 33 + 1 = 28
     
 
28. Answer The horizontal line one unit above the x axis.
29. Answer The vertical line 3 units to the left of the y axis.
     
     
30. Answer The graph of  2x + 3y = 2   is
To graph 2x + 3y = 2, we need to find any two points which lie on the line
and connect them with the straight edge. There are several ways to do this.
    We outline two common methods.
Intercept method:
     
If we let x = 0, the y intercept is 3y = 2 or
    and if we let y =0 the x intercept is (1,0)
     
Slope-Intercept method:
     
Solving for y in the form y = mx + b we get:
From this form we see that the y intercept is
From this point we can use the slope, which is
    to find a second point by moving, 2 units to the left (0 – 2 = – 2)
   
and 3 units up to get the second point