
Step-by-step explanation
let

Step 1
A) solve by substitution or elimination
isolate x in equation (2) and then replace in equation (1)

now, replace the x value in equation (1) and isolate y

finally, replace the y value we just got, in equation (3) to find x

so, the solution of the system of equation is

Step 2
briefly describe how you can prove that the solution found in part A is correct:
to prove this we need to replace the values we found, and the equation becomes a true equality
so,
for equation(1)

now, equation (2)

therefore, as we said in the previous part
the solution is

I hope this helps you