SOLUTION: solve the system using substitution: 4x-3y=-6 -x-2y=7 i got some weird answer on my quiz and i got it wrong i just want to see what i did wrong

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Question 992935: solve the system using substitution:
4x-3y=-6
-x-2y=7
i got some weird answer on my quiz and i got it wrong i just want to see what i did wrong
Found 3 solutions by josgarithmetic, ikleyn, MathTherapy:
Answer by josgarithmetic(39618) About Me  (Show Source):
You can put this solution on YOUR website!
You would need to show all your steps.

You want to solve using substitution.
system%284x-4y=-6%2C-x-2y=7%29

Simplest may be
-x=2y%2B7
x=-2y-7
Now substitute into the other equation.
4%28-2y-y%29-3y=-6
4%28-3y%29-3y=-6
4%283y%29%2B3y=6
15y=6
y=6%2F15
highlight%28y=2%2F5%29

x=-2%282%2F5%29-7
x=-4%2F5-7
x=-4%2F5-35%2F5
highlight%28x=-39%2F5%29

Answer by ikleyn(52794) About Me  (Show Source):
You can put this solution on YOUR website!
.
You want to solve using substitution.
system%284x-3y=-6%2C%0D%0A-x-2y=7%29

Simplest may be
-x=2y%2B7
x=-2y-7
Now substitute into the other equation.
4%28-2y-7%29-3y=-6
-8y-28-3y=-6
-11y=-6%2B28
-11y=22
y=-2
highlight%28y=-2%29

x=-2y-7
x=4-7
x=-3
highlight%28x=-3%29

Answer by MathTherapy(10552) About Me  (Show Source):
You can put this solution on YOUR website!
solve the system using substitution:
4x-3y=-6
-x-2y=7
i got some weird answer on my quiz and i got it wrong i just want to see what i did wrong
 4x - 3y = - 6 ------- eq (i)

- x - 2y =   7 ------- eq (ii)

The easiest way to apply substitution is to solve the 2nd equation for x, since the coefficient of x is - 1

Solving the 2nd equation for x results in: x = - 2y- 7 

4(- 2y - 7) - 3y = - 6 ------ Substituting - 2y - 7 for x in eq (i)

- 8y - 28 - 3y = - 6

- 11y = 22

y = 22%2F%28-+11%29, or highlight_green%28-+2%29

Substitute - 2 for y in eq (ii) to get the value of x as:highlight_green%28-+3%29