algebra 1
posted by rachel .
solve by substitution.
0.5x+0.25y=36
y+18=16x

y + 18 = 16 x
y = 16 x  18
______________
0.5 x + 0.25 y = 36
x / 2 + y / 4 = 36 Multiply both sides with 4
4 x / 2 + 4 y / 4 = 36 4
2 x + y = 144
2 x + 16 x  18 = 144
18 x = 144 + 18
18 x = 162 Divide both sides with 18
x = 162 / 18
x = 9
y = 16 x 18
y = 16 9  18
y = 144  18
y = 126
Solutions :
x = 9 , y = 126
Proof :
0.5 x + 0.25 y = 36
x / 2 + y / 4 =
9 / 2 + 126 / 4 =
18 / 4 + 126 / 4 =
144 / 4 = 36
y + 18 = 16x
126 + 18 = 16 9
144 = 144