Answer:
Isolate one variable in one of the equations and substituting it into the other equation. *note* in example the first substitution is given to you
Explanation:
For example:
-3x-4y=-2
y=2x-5
Substitute -4y with second equation
-3x-4(2x-5)=-2
PEMDAS
-3x-8x+20=-2
-11x+20=-2
Subtract 20 on both sides of the = sign
-11x=-22
Divide both sides
x=2
Plug that into the second equation
y=2(2)-5
y=4-5
y=-1