Question

Solve the system by substitution.

x=9y
x-5y=20

Answer 1

Answer:

x-5=20

9y-5y=20

4y=20

4y÷4=20÷4

y=5

x=9y

x=9×5

x=45

Answer 2

X=9y
9y-5y=20
4y=20
Therefore y=5
Substitute y=5 into eqn 1
X=9*5
X=45