Download Solving Fraction Equations by Multiplying

Solving Fraction
Equations by
Multiplying
Lesson 5-5
If the variable is in the
fraction…
• When the variable is the numerator of the
fraction, then it suggests a division
problem.
• To solve a division problem, the inverse
operation is multiplying.
Example
y
8
= 20
This equation reads “y divided by 8 equals
20.”
The opposite of dividing by 8 is multiplying
by 8.
Multiply both sides by 8.
y
18
20
8
·
=
·
81
1
y
= 160
1
y = 160
Example 2
1 2 · m = 3· 2
1
21
m =6
1
m =6
Check answers in the original
equation.
m
=
3
2
6 =3
2
3 =3
If the variable is being multiplied
by a fraction…
• To isolate a variable that is being
multiplied by a fraction, multiply by the
reciprocal.
• Perform the same operation on the other
side of the equation.
Example
5
1 3 1 2 r = 10 · 3
·
12 13
1 21
1 r = 15
1
r = 15
Homework Time