Does anyone know the answer for 7 and 8?

7) A    8) C

Step-by-step explanation:

number 7 tells us that y=x+1

so we just basically plug it in

2x+3(x+1)=4   A

to eliminate x's in number 8, we have to multiply one of the equations by -1

let's multiply the second one

4x+3y=6

4x ·-1-y·1=2·-1

4x+3y=6

-4x+y=-2

x's eliminate

4y=4, meaning that the answer is C

C is the answer\

Step-by-step explanation: