Review Exercise Set 15
Exercise 1:
Solve for n.
n
6
5
Exercise 2:
Solve for x.
5 x 1
 
9 3 9
Exercise 3:
Solve.
4a = 15
Exercise 4:
A number plus one-fifth equals one-third. Find the number.
Exercise 5:
Negative two-thirds is equal to one-fourth times a number. Find the number.
Review Exercise Set 15 Answer Key
Exercise 1:
Solve for n.
n
6
5
Multiply both sides of the equation by the denominator of 5 to eliminate the fraction
n
5  65
5
n
5
1
1
 5  65
n  30
Exercise 2:
Solve for x.
5 x 1
 
9 3 9
Isolate the fraction with the variable by subtracting one-ninth from both sides
5 1
 
9 9
5 1
 
9 9
5 1

9
4

9
x 1 1
 
3 9 9
x
3
x
3
x
3
Multiply both sides of the equation by the denominator of 3 to eliminate the fraction
4
x
3  3
9
3
1
1
4
x
3  13
1
3 3
3
4
x
3
1
1 x
3
Exercise 3:
Solve.
4a = 15
Divide both sides by 4
4a 15

4
4
1
4 a
4
1

15
4
15
4
3
a3
4
a
Exercise 4:
A number plus one-fifth equals one-third. Find the number.
Begin by assigning a variable to represent the unknown number
Let n = a number
Now, setup the equation that needs to be solved based on the information given.
Solve for the variable
1 1 1 1
n   
5 5 3 5
1 1
n 
3 5
1 5 1 3
n

3 5 5 3
5 3
n 
15 15
2
n
15
Exercise 5:
Negative two-thirds is equal to one-fourth times a number. Find the number.
Assign a variable to unknown number
Let n = a number
Setup the equation
Solve for the variable
2 1
 n
3 4
2
1
4   4  n
3
4
8
 n
3
2
2  n
3
