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-3x+5y=4 and x+y=-4 find the value of x and y

User Ptay
by
5.2k points

1 Answer

6 votes

Answer:

x = -3, y = -1

Explanation:

Solve by substitution:

First make the second equation in terms of y:

y = -x-4

Next, since we found what y is, plug it into the first equation and solve for x:

-3x + 5(-x-4) = 4 Plug in

-3x - 5x - 20 = 4 Distribute

-8x - 20 = 4 Simplify

-8x = 24

x = -3

We have found that x = -3. To find y we need to plug x back into any of the equations. Let's do equation #2.

(-3) + y = -4 Plug in

y = -1 Simplify

So, y = -1 and x = -3. Let's check this in the first equation to make sure it is correct:

-3(-3)+ 5(-1) = 4 Plug in

9 + (-5) = 4 Simplify

9 - 5 = 4

4 = 4

Since both sides are equal that means we are correct!

Hope this helps!!

User Tom Norton
by
6.1k points
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