How do I use substitution to find the solution of the system of equations y=1/3x+7/3 and y=-5/4x+11/4?

1 Answer
Sep 26, 2014

In this problem we have 2 different expressions that represent the value of y. Because they both represent y we can set them equal to each other.

(1/3)x+7/3=-(5/4)x+11/4

Because all of the terms share a common multiple of 12 I will multiply each term by 12 to eliminate the fractions.

12[(1/3)x+7/3=-(5/4)x+11/4]

[(12/3)x+84/3=-(60/4)x+132/4]

4x+28=-15x+33

19x=5

x=5/19

Substitute in this newly found x-value into one of the original equations.

y=(1/3)x+7/3

y=(1/3)*(5/19)+7/3

y=(5/57)+7/3*19/19

y=5/57+133/57

y=138/57

y=46/19