Question

Solve this system of equations by using the substitution method...
y - 2x = 5
-2y + 7x = -4

Answer 1

isolate y in y - 2x = 5 to get

y - 2x = 5

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

y = 5+2x

Answer 2

then plug this into the second equation

-2y + 7x = -4

-2(5+2x) + 7x = -4 ... replace y with 5+2x (since the two are equal)

now solve for x

Answer 3

once you get x, you can find y

Answer 4

K. Thanks !

Answer 5

yw

Answer 6

when I plug that equation in...I got confused

Answer 7

so you're still stuck? or you know what to do now?

Answer 8

I thought I had it , then all of a sudden I got confused.. after plugging it in I got
-10 - 4x + 7x = -4 ... is that right ?

Answer 9

so far so good

Answer 10

then add -10 to both sides?

Answer 11

just 10, so add 10 to both sides

Answer 12

then I get -4x+7x=6 .. right?

Answer 13

good

Answer 14

keep going

Answer 15

then I got 3x=6 and then divided both sides by 3 and x =2 , now all I do is plug in the 2 to the other equation & I get my answer ! : )

Answer 16

yep x = 2

Answer 17

y = 5+2x

so you just plug x = 2 into that to find y

Answer 18

y = 9 !

Answer 19

correct

Answer 20

Thank you so much !

Answer 21

yw