Thread: Confused

I need help with a problem.

I worked it out but I think I'm wrong. Can some one please help solve this correctly?

Use substitution to solve: 2x + y = 7
5x - 2y = 4


My answer:

y = 7 - 2x
7x - (7-2x) = 11
7x - 7 + 2x = 11
2 7
9x 18
9x/9 = 18/9
y=2

5x - 2y = 4
5x-2(2)=4
this is where I'm lost.

Can someone help me.

you were doing fine until
"...9x/9 = 18/9
y=2"

You were solving for x and then you said y = 2?
Should it not be x = 2?

Ok thank you.

so that is x = 2

then:

5x - 2y = 4
5(2) - 2y = 4
10 - 2y = 4
2y = 14

y = 7

No.
y = 3.

Why is
2y = 14 ?

5x - 2y = 4
5(2) - 2y = 4
10 - 2y = 4
-2y = 4 -10
-2y = -6
y = -6 / -2
y = 3

O.i.c where I made my mistake. THank you for the help.