Question

Equation for y.
1. 2x + y = -9
2x+y=-9

Answer 1

Infinitely many solutions (If its solved by systems of equations)

y = -2x - 9 (if you ONLY want to solve for y)

Explanation:

Well you can solve this is 2 ways. Substitution and Elimination

SUBSTITUTION

2x + y = -9

2x+y=-9

Step 1: Solve 2x+y =−9 for y:

2x+y=−9

2x+y+−2x=−9+−2x(Add -2x to both sides)

y=−2x−9

Step: Substitute −2x−9 for y in 2x+y=−9:

2x+y=−9

2x+−2x−9=−9

−9=−9(Simplify both sides of the equation)

−9+9=−9+9(Add 9 to both sides)

Final answer -----> 0=0

ELIMINATION

2x + y = -9

2x+y=-9

Step 1: Multiply the second equation by -1, then add the equations together.

(2x + y = -9)

-1(2x+y=-9)

Which then becomes:

2x + y = -9

-2x - y = 9

Step 2: Add these equations to eliminate x:

Final answer -----> 0 = 0

Answer 2

If you want to solve for y, then you would get y = -2x-9

This is the result after subtracting 2x from both sides. This is so we can undo the +2x that happens to the y variable.