Question

(08.05)

Answer 1

If you use the first answer, the equation becomes 2x + 2y = 16.  You could subtract this from equation Q to eliminate x.

The second answer makes equation P -2x - 2y = -16.  You could add this to equation Q to eliminate x.  You can use both of these methods to eliminate the x term, but if you can only choose one, you should choose the second option.

Answer 2

Answer is −2(x + y = 8)
cause

−2(x + y = 8) (multiply -2 to 1st equation)
-2x - 2y = - 16
 2x + 5y = 24
--------------------add
 0 + 3y = 8 (eliminate x to solve for y)