Question

What is the value of y in the solution to the system of equations 5x-y=25 and x+4y=-10

Answer 1

x+4y =10

5x-y =25

Explanation:

x=10-4y

5(10-4y)-y =25

50-20y-y =25

50-21y = 25

-21y = 25-50

-21y =-25

y =25/21

Substitute y =25/21 in equation 1

x + 4(25/21) = 10

x +100/84 =10

x=10-100/84

Answer 2

y=-3.571

Explanation:

To get rid of the x's make the other x cancel out the other.

5x-y=25+(-5(x+4y=-10)=-21y=75= -3.571