Using substitution, solve this equation..

Question

3x - 5y = 11
x - 3y = 1

Answer 1

Equation 2 looks like it would be easy to solve for x, so we take it and isolate x:

x - 3y = 1

x = 1 + 3 y

Now we can use this result and substitute x = 1 + 3 y in for x in equation 1:

3x - 5y = 11

3 * ( 1 + 3 y ) - 5 y = 11

3 + 9 y - 5 y = 11

3 + 4 y = 11

4 y = 11 - 3

4 y = 8 Divide both sides with 4

y = 2

x = 1 + 3 y

x = 1 + 3 * 2

x = 1 + 6

x = 7