posted by asia .
how would i use substitution for the equations x+y=56 and x+(3y)=56
Isolate x or y in either equation and then subsitute it in to the other equation.
Subsitute into the other equation:
Since x=56-y, the other equation becomes (56-y)+3y=56
56+2y=56 subtract 56 from both sides
then x must be 56