Breann solved the system of equations below. what mistake did she make in her work?

2x + y = 5
x − 2y = 10

y = 5 − 2x
x − 2(5 − 2x) = 10
x − 10 + 4x = 10
5x − 10 = 10
5x = 20
x = 4

2(4) + y = 5
y = −3

As far as i am concerned, i do not find any mistake with the answer and the procedure of the problem that has been solved by Breann. It has been done correctly. The value of "x" and "y" are absolutely correct. I hope that this will boost your confidence and help you solve problems of similar nature with absolute ease.