Question

Solve the following system of equations by using the substitution method.

x = y + 3
2x + y = 9

Answer 1

Substitute for x in the second equation:-

2(y + 3) + y = 9

2y + 6 + y = 9

3y = 9 - 6 = 3

so y = 3/3 = 1

Now plug this value of y into first eqution:-

x = 1 + 3 = 4

So you answer is x = 4 and y = 1.

Explanation:

Answer 2

Substitute for x in the second equation:-

2(y + 3) + y = 9

2y + 6 + y = 9

3y = 9 - 6 = 3

so y = 3/3 = 1

Now plug this value of y into first eqution:-

x = 1 + 3 = 4

So you answer is x = 4 and y = 1.