Question

y=-x+5 and x-y=-1

Answer 1

rearrange to get

x+y = 5
x-y = -1
add the equations to get
2x = 4
x = 2
so, y=3

or, using substitution,, since y = -x+5,
x-y = -1
x-(-x+5) = -1
2x-5 = -1
2x = 4
...