Question

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

Answer 1

Well, If i'm Not Mistaken Breann Did Not Make A Mistake...She Did Everything Right.

Answer 2

let me see....
2x + y = 5
x - 2y = 10

y = 5 - 2x (she used the 1st equation and solved for y) correct
x - 2(5 - 2x) = 10 (she subbed 5 - 2x in for y in 2nd equation) correct
x - 10 + 4x = 10 (she multiplied through the parenthesis) correct
5x - 10 = 10 (she combined like terms) correct
5x = 20 (she got 5x by itself) correct
x = 4 (she solved for x) correct

2(4) + y = 5 (she subbed 4 in for y in the 1st equation) correct
8 + y = 5 (she skipped this step but you wouldn't need to write this)
y = - 3 (she solved for y) correct

check...(I am just doing this for myself)
x - 2y = 10
4 - 2(-3) = 10
4 + 6 = 10
10 = 10 (correct)

There is nothing wrong with Breann's answer. It is correct.

By the way....wow....what a username u got (lol)....what made you decide to pick that one ....ROFL