X+Y=-5 / Y=-4x+7

Question

Use any method. Please show work. NEED HELP BADLY

Answer 1

Easier to use substitution:

x + y = -5, so x = -5 - y

y = -4x + 7 → y = -4(-5 - y) + 7 → y = 20 + 4y + 7

Combining like terms and getting the y's on one side -3y = 27

y = 27/-3 → y = -9

So x = -5 - (-9) x = 4

Answer 2

Hi Jay

Again as I mentioned in your other problem if your / is just there to separate equations then the following could be applied

Equation 1

x + y = -5

Equation 2

y = -4x + 7

Getting the variables on one side of Equation 2 we have

4x + y = 7

We can combine Equation 1 and Equation 2 with Elimination as follows

x + y = -5

4x +y = 7

Multiply Equation 1 by negative one then add it to Equation 2

-x - y = 5

4x + y = 7

Y is eliminated

3x = 12

Divide both sides by 3

x = 4

Go back and substitute 3 for x in Equation 2 to solve for y

4(4)+ y = 7

16 + y = 7

y = 7 - 16

y = -9

Checking in the original equations

x + y = -5

4 - 9 = -5

y= -4x + 7

-9 =-4(4) +7

-9 = -16 + 7

-9 = -9

You can apply the same to your other question but you should clarify your / mark.