SOLUTION: elimination of multiplication 7x+4y=-4 5x+8y=28

Question 682978: elimination of multiplication 7x+4y=-4
5x+8y=28
Answer by DrBeeee(684) (Show Source): You can put this solution on YOUR website!
Given:
(1) 7x + 4y = -4 and
(2) 5x + 8y = 28
I'm not exactly sure what "elimination by multiplication" means, but I interpert it as meaning that you multiply one of the equations by by a number that allows you to eliminate one of the variables after you add or subtract the new equation from the other. If this method is what is wanted, let's multiply (1) by -2 and get
(3) -14x - 8y = 8
Now add (2) and (3) to get
(4) -9x + 0 = 36 or
(5) x = -4
Now put (5) into (1) and get
(6) 7(-4) + 4y = -4 or
(7) 4y = 24 or
(8) y = 6
Let's check the values of x and y using (2).
Is (5(-4) + 8*6 = 28)?
Is (-20 + 48 = 28)?
Is (28 = 28)? Yes
Answer: The solution pair is (-4,6)
RELATED QUESTIONS
7x + 4y = -4 5x + 8x = 28 how do you solve the system of equations by... (answered by persian52)

2x - 3y = 2 5x + 4y = 28 to solve this problem use elimination of... (answered by dabanfield)

Use elimination to solve each system of equations. I have to show all work and write the... (answered by ikleyn)

Use elimination to solve each system of equations. I have to show all work and write the... (answered by ikleyn,ankor@dixie-net.com)

I need help! solve each system of equations by elimination 5x - 4y = 23 7x + 8y... (answered by iluvbuilding429)

I need help! solve each system of equations by elimination 5x - 4y = 23 7x + 8y... (answered by benni1013)

Solve using elimination: 5x + 3y = 28 2x + 4Y = -... (answered by ankor@dixie-net.com)

5x+4y=22 7x+6y=34 Using Matrix... (answered by lynnlo)

Solve each system of equation by elimination. Show your work. a. (6,a) b. (-4,b) c.... (answered by solver91311,Seutip)