Question

how do i solve
y=4y and
x+y=5 while solving systems by subtitution

Answer 1

Subtract y from both sides to get 0=3y and 5=y+x Multiply this one by -3 to get -15=-3y-3x The Ys cancel and you get -3x=-15 solve for x and substitute it in the y equation to check (y should be 0)