Question

solve for y in the following system of equations

x-y=-1
3x+5y=21

Answer 1

x = y-1
3y -3 +5y =21
8y=24
y=3
x = 2

Answer 2

could you please explain the first two steps briefly?

Answer 3

x - y = -1
x = y -1
add y both sides
then 3(x) +5y = 21
3(y-1)+5y =21