Question

Solve the following system of equations by the substitution method.

10x + 10y = 1
x = y - 3

What is the value of y?

-29/20
31/20
-3/2

Answer 1

31/20 is the correct answer

Answer 2

Answer: 31/20

Explanation:

10x + 10y = 1 ---------(1)

x = y - 3

substituting x = y - 3 in equation (1)

10(y - 3) + 10y = 1

10y - 30 + 10y = 1

20y - 30 = 1

20y = 1 + 30

20y = 31

divide 20 by bothside

20y/20 =31/20

y=31/20