Carlos 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

He should have substituted 5 + 2x

He did not distribute correctly

He combined like terms incorrectly, it should have been 4x instead of 5x

He made no mistake

Question

Carlos 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 

He should have substituted 5 + 2x 

 He did not distribute correctly 

 He combined like terms incorrectly, it should have been 4x instead of 5x 

 He made no mistake

anonymous · Answer

He made no mistake

anonymous · Answer

It appears he distributed -2 to +5 incorrectly. Should be x - 10 + 4x

anonymous · Answer

So sai123 is wrong?

anonymous · Answer

He may have overlooked the distribution. But that is what I see. You would have 5x = 20 -> x = 4

anonymous · Answer

srry  he is crrct x + 10 + 4x = 10  has mistake

anonymous · Answer

So which one is the answer?

anonymous · Answer

"He did not distribute correctly"

anonymous · Answer

Okay Thank you !

anonymous · Answer

He did not distribute correctly