Problem: what is 4x+2y=86
also x+y= 24
This must be a system of equations, to be
solved simultaneously.
1) 4x + 2y = 86
2) x + y = 24
x + y = 24
x = -y + 24
Substitute that into equation 1.
4x + 2y = 86
4(-y + 24) + 2y = 86
-4y + 96 + 2y = 86
-2y + 96 = 86
-2y + 96 - 96 = 86 - 96
-2y = -10
-2y/-2 = -10/-2
y = 5
Solve for x.
x + y = 24
x + 5 = 24
x + 5 - 5 = 24 - 5
x = 19
Check.
4x + 2y = 86
4(19) + 2(5) = 86
76 + 10 = 86
86 = 86
Answer: x = 19, y = 5