Solve by substitution method

9x+6y=21-9x+y=35
What is the solution of the method?

1 answer

Those are two separate equations. You should have typed:

9x + 6y = 21
-9x + y = 35

You can either add them, or SUBSTITUTE y-35 for 9y in the first equation. Either way, you get
7y = 56
y = 8
9x + 48 = 21
x = -3