How do you solve the following system?: x+3y=8,6x+4y=3

1 Answer
May 12, 2018

The values x=21314 , y=3914 fulfills both equations.

Explanation:

It is always helpful to start with drawing the two equations as graphs in a diagram, not least as a check that our solution makes sense:

enter image source here

We want to find a value of x and y which fulfill both equations at the same time, i.e. it must be on both lines f and g on the figure above.

As x+3y=8, it follows that
(1) x=3y+8

Insert this value for x in the second equation. To make the solution simpler to follow I will write it as 3=6x+4y, that is:
3=6x+4y=6(3y+8)+4y
3=18y+48+4y=14y+48

The last expression can be written as
14y=48+3=51 or y=5114=3914

Insert this in expression (1):
x=3y+8=(3)5114+8=35181414
x=153+11214=4114=21314

Our solution, therefore, is
x=21314 , y=3914

If we convert these two values to decimal numbers, we see that it agrees with our graph.