Math Word Problems Demystified - A Self Teaching Guide

4 xþ 3 y¼ 1

4 x
 4 xþ 3 y¼ 1 
 4 x

3 y¼ 1 
 4 x

31 y

31

¼

1 
 4 x

3

y¼

1 
 4 x

3

Step 2: Substitute in the first equation.

5 x
 7 y¼
 31

5 x
 7 

ð 1 
 4 xÞ

3

¼
31

Clear fractions.

3  5 x

31

1



7 ð 1 
 4 xÞ

31

¼
31  3

15 x
 7 ð 1 
 4 xÞ¼
 93

15 x
 7 þ 28 x¼
 93

43 x
 7 þ 7 ¼
 93 þ 7

43 x¼
 86

431 x

431

¼

86

43

x¼
 2

Step 3: Findy.

4 xþ 3 y¼ 1

4 ð
 2 Þþ 3 y¼ 1

 8 þ 3 y¼ 1

 8 þ 8 þ 3 y¼ 1 þ 8

REFRESHER V Systems of Equations 201