You can put this solution on YOUR website! x + y = 12
y = 2x
.
Substitution means to substitute one equation for a term in the other eqation.
Pick the simpliest equation and solve for one of the variables (if not already solved):
y=2x
.
Substitute y=2x back into the other equation and solve.
x+y=12 [substitute y=2x for y]
x+(2x)=12
3x=12
3x/3=12/3
x=4
.
Plug x=4 back into either equation and solve for the missing equation.
x+y=12
4+y=12
y=12-4
y=8
.
Check by plugging x=4 and y=8 back into both equations.
x+y=12
4+8=12
12=12 [checks out]
and y=2x
8=2(4)
8=8 [also checks out]
