SOLUTION: Please Help. Use elimination to solve each system of equations. 7M+4N=2 7M+2N=8

Algebra ->  Coordinate Systems and Linear Equations -> SOLUTION: Please Help. Use elimination to solve each system of equations. 7M+4N=2 7M+2N=8      Log On


   

Question 182618: Please Help.
Use elimination to solve each system of equations.
7M+4N=2 7M+2N=8
Answer by jojo14344(1513) About Me  (Show Source):
You can put this solution on YOUR website!

Given:
7M%2B4N=2--------> EQN 1
7M%2B2N=8--------> EQN 2
Let system%28M=highlight%28x%29%2CN=highlight%28y%29%29
Multiply EQN 2 by 2 and subtract from EQN 1:
EQN 2, (7x+2y=8)(2)=14x%2B4y=16
Then,
7x+4y=2, EQN 1
-(14x+4y=16), New EQN 2 * remember to change signs
------------
-7x=-14------>cross%28-7%29x%2Fcross%28-7%29=cross%28-14%292%2Fcross%28-7%29
highlight%28x=2=M%29, subst. in NEW EQN 2:
14%2A2%2B4y=16
4y=16-28=-12 -------->cross%284%29y%2Fcross%284%29=cross%28-12%293%2Fcross%284%29
highlight%28y=-3=N%29
It shows, both eqns will meet at point (2,-3):
------>RED>>>> EQN 1; GREEN>>> EQN 2
Thank you,
Jojo