Respuesta :

3x-10y=-25
4x+40y=20

12x-40y=-100
12x+120y=60

-160y=40

y=1/4
x=5/2


3x-10y=-25Add 10y10y to both sides
        3x=−25+10y

Regroup terms
3x=10y-253x=10y−25
Divide both sides by 3
x=10y-25/3

Factor out the common term 5
your answer: x=5(2y-5)/3

4x+40y=20
Factor out the common term 4
4(x+10y)=20
Divide both sides by 44
x+10y=20/4

Simplify 20/4 to 5
x+10y=5

Subtract 10y10y from both sides
your answer:  x=5-10y