Question

If 3x+20=2y and x+5=y show that (2,7) is a solution solve by substitution. PLEASE ANSWER ME

Answer 1

Well, 2 is x and 7 is y correct? so you would just do it like this

3x+20=2y
x+5=y

3(2)+20=2(7)
2+5=7

Answer 2

Subsitute x+5 for y
3x+20=2(x+5)
3x+20=2x+10
minus 2x both sides
x+20=10
minus 20
x=-10
sub back

x+5=y
-10+5=y
-5=y


x=-10
y=-5
(x,y)
(-10,-5)


(2,7) is not a solution