Substitute forxin the second equation and solve fory.
4 yþ 10 ¼ 2 yþ 20
4 y 2 yþ 10 ¼ 2 y 2 yþ 20
2 yþ 10 ¼ 20
2 yþ 10 10 ¼ 20 10
2 y¼ 10
21 y
21
¼
10
2
y¼ 5
Solve forx:
x¼ 4 y
x¼ 4 5
x¼ 20
Matt is 20 and Mike is 5 years old.
- Letx¼the number of bags of $0.50 candy
andy¼the number of bags of $0.75 candy
xþy¼ 40
50 xþ 75 y¼ 2325
Solve foryin the first equation.
xxþy¼ 40 x
y¼ 40 x
224 LESSON 18 Using Two Equations