SOLUTION: 3x+y=-3 and y=x+5 express answers as ordered pair. i'm suck on this.. (3,-2) (-2,3) (-4/3, 1) (-8/3, -3) these are my choices. i know its a or c but it doesn't wor

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: 3x+y=-3 and y=x+5 express answers as ordered pair. i'm suck on this.. (3,-2) (-2,3) (-4/3, 1) (-8/3, -3) these are my choices. i know its a or c but it doesn't wor      Log On


   

Question 870214: 3x+y=-3 and y=x+5 express answers as ordered pair. i'm suck on this..
(3,-2)

(-2,3)

(-4/3, 1)

(-8/3, -3)
these are my choices. i know its a or c but it doesn't work..
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
Start with 3x+y=-3 and plug in y=x+5. This works because y is isolated in the second equation.


3x%2By=-3


3x%2Bx%2B5=-3 Replace EVERY copy of y with x+5. Now solve for x


4x%2B5=-3


4x=-3-5


4x=-8


x=-8%2F4


x=-2


So we can see that the answer must be choice B) since that's the only choice with x = -2. But let's finish up.


Since x=-2, we can use this to find y. Plug it into any equation with x,y in it. The easiest to pick on is the one with y already isolated


y=x%2B5


y=-2%2B5 Replace EVERY copy of x with -2 (since we now know x+=+-2)


y=3


Since x=-2 and y=3, the final answer is (x,y) = (-2,3) which is choice B)