Question

If 2x+y=4 and 2x-y=8, then what does 3x-y equal?

Answer 1

THE TRICK IS TO FIND THE VALUE OF X AND Y FIRST.

I WILL USE SUBSTITUTION TO SOLVE THIS SYSTEM OF EQUATIONS.

`y = 4 - 2x......(3)equation`

`2x - (4 - 2x) = 8 \\ 2x - 4 + 2x = 8 \\ 2x + 2x = 8 + 4 \\ 4x = 12 \\ (4x)/(4) = (12)/(4) \\ x = 3`

`y = 4 - 2(3) \\ y = 4 - 6 \\ y = - 2`

THEN FOR 3X-Y PLUG IN THE VALUES YOU FOUND FOR X AND Y

`= 3(3) - ( - 2) \\ = 9 + 2 \\ = 11 \\ 3x - y = 11`

ATTACHED IS THE SOLUTION