identify the solution(s) of the system of equations if any x+2y=4, 9x-4y=3

Question

identify the solution(s) of the system of equations if any x+2y=4, 9x-4y=3

Answer 1

In order to solve this type of question, use the following method. Make either one or the other equation cancel out either the "x" or "y."

 

This is achieved by the following:

 

(x+2y=4)*2= 2x+4y=8
9x-4y=3

 

adding these systems together you get:

 

2x+4y=8

9x-4y=3

 

11x=11

 

then divide each side by 11

 

11x=11

___  ___

 

11    11

 

x=1

 

Then plug in this to the original equation.

 

1+2y=4 or 9-4y=3

2y=3 y=3/2 or -4y=-6 or y=3/2 as well.

 

This means that y=3/2 and x=1

 

To check once more.

 

1 + (3/2)*2 = 4
1+3=4
4=4 yes

 

9-4*(3/2)=3

9-6=3

3=3 yes

 

Please note that I solved for "x" first. Solving for "y" first can also be done.