Answer:
C
Step-by-step explanation:
What you do on one side of the equation, you do to the other. She added 10x on the right side and subtracted 10x on the left when she should have added 10x on both sides.
that is literally gibberish
x = -2.9
y = 2.6
x+y = -2.9+2.6
= -0.3
X=4
I'm took lazy to explain it step by step sorry, but I'm positive that's the correct answer.