Solve foryin the first equation.
y¼ 14 x
Substitute in the second equation and solve forx.
10 xþð 14 xÞþ 18 ¼ 10 ð 14 xÞþx
10 xþ 14 xþ 18 ¼ 140 10 xþx
9 xþ 32 ¼ 140 9 x
9 xþ 9 xþ 32 ¼ 140 9 xþ 9 x
18 xþ 32 ¼ 140
18 xþ 32 32 ¼ 140 32
18 x¼ 108
181 x
18
¼
108
18
x¼ 6
Solve fory:
xþy¼ 14
6 þy¼ 14
6 6 þy¼ 14 6
y¼ 8
- Letx¼the number of nickels
andy¼the number of dimes
xþy¼ 18
5 xþ 10 y¼ 130
222 LESSON 18 Using Two Equations