Question

Solve the system of equations by substitution x+y=18, y=5x

Answer 1

One way to do it is

Plug in y so 5y + x =18

Divide both sides by 5 to get y alone

Subtract the answer of 18÷5 =3.6

3.6- 18 = 14.4

14.4 is your answer

Answer 2

(3, 15 )

Explanation:

Given the 2 equations

x + y = 18 → (1)

y = 5x → (2)

Substitute y = 5x into (1)

x + 5x = 18

6x = 18 ( divide both sides by 6 )

x = 3

Substitute x = 3 into (2) for corresponding value of y

y = 5(3) = 15

Solution is (3, 15 )