Question

Trevor solved the system of equations below. What mistake did he make in his work?

2x + y = 5
x - 2y = 10

y = 5 - 2x
x - 2(5 - 2x) = 10
x - 10 + 4x = 10
5x - 10 = 10
5x = 0
x = 0

2(0) + y = 5
y = 5
Answer
He made no mistake
He combined like terms incorrectly, it should have been 4x instead of 5x
He should have substituted 5 + 2x
He subtracted 10 from the right side instead of adding 10 to the right side

Answer 1

He subtracted 10 from the right side instead of adding 10 to the right side

Answer 2

thanks:D

Answer 3

10 should be added