Question

Solve by the substituion method
3x-7y=43
9x+71=y

Answer 1

have you tried them? where are u stuck.

Answer 2

?

Answer 3

Saifoo, not giving answers anymore?

Answer 4

Heck no.

Answer 5

I see it as laziness now.

Answer 6

LOL.

Answer 7

3x-7y=43
9x+71=y

Substitute your y from the second equation into the first equation.

3x-7(9x+71)=43

Now your equation has one variable and can be solved like a normal equation.
3x-7(9x+71)=43
Expand the brackets
3x-63x-497=43
Gather like terms
-60x= 540
x = -9

Substitute this back one of the original equations, doesn't matter which one.
9x+71=y
9x-9+71 = y
-81+71 = y
y = -10