Hey there! I'm happy to help!
SYSTEM #1
-4x+2y=22
-y=-3x-9
We can multiply both sides of the second equation by -1 to see what y equals.
y=3x+9
We can substitute this value for y into the first equation and solve for x.
-4x+2(3x+9)=22
We use distributive property to undo the parentheses.
-4x+6x+18=22
We combine like terms.
2x+18=22
Subtract 18 from both sides.
2x=4
Divide both sides by 2.
x=2
Our x has to be -4 to be the correct answer, so this option is incorrect.
SYSTEM #2
-4x+2y=22
y=-3x-9
We plug this y value into the first equation to solve for x.
-4x+2(-3x-9)=22
We use distributive property to undo the parentheses.
-4x-6x-18=22
We combine like terms.
-10x-18=22
Add 18 to both sides.
-10x=40
x=-4
We have the correct x-value to be the answer, so let's find the y-value by plugging our x-value into one of the equations.
y=-3(-4)-9
y=12-9
y=3
So, the solution of this system of equations is (-4,3), so the correct answer is 2. -4x+2y=22, y=-3x-9
Have a wonderful day! :D
