solving system of equations by elimination?

Question

-4x-2y=-12
4x+8y=-24

Answer 1

Add:-
6 y = - 36
y = - 6

4x - 48 = - 24
4x = 24
x = 6

x = 6 , y = - 6

Answer 2

Ok look at the two equations

-4x -2y = -12
4x +8y= -24
==========

What's the best thing to do to eliminate one of the variables? Lets add the two equations.

The result
6y = -36
y =-6.

Substitute in the first one
-4x -2(-6) = -12
-4x +12 = -12
-4x =-24
x = 6

so the answer is x = 6, y=-6

Hope this helps!

Answer 3

elimination method is fairly simple because you're adding/subtracting to get rid of either x or y (variables). Using this method, you must make sure that at least one variable (for instance x) in both the first and second equation adds up to 0 ( you might have to mutiply or divide the whole equation if necessary). Once you have the value for either x or y, you could solve the other unknown variable.
This equation is simple because the x's in both equations are already the same value; therefore, you could add the two equation together to get rid of the x and isolate the y-value.
-4x-2y=-12
+(4x+8y=-24)
= 0x+6y=-36
4y=-36 ;divide both sides by 4
y=-6

Then substitute the y-value back into the one of the original equations to find the value of x

-4x-2y=-12
-4x-2(-6)=-12
-4x+12= -12; substract 12 from both sides

=-4x =-24; divide both sides by -4
x=6

To check: Substitute the x and y value into one of the original equation to see if it works

4(6)+8(-6)=-24; correct

Answer 4

Ok, basically you don't have to do anything to this one in order to solve it. As it is written, the two x terms will cancel one another out when you add the equations together (they are the same term with opposite signs). Thus, add as follows

-4x-2y = -12
4x+8y = -24
__________
6y = -36

Solve for y

y= -6

Plug this value into one of the two original equations to get x:

4x +8(-6) = -24
4x -48 = -24
4x = 24
x = 6

Now substitute the newly found x and y value in and make sure that they satisfy both equations (they do).

I hope that helped.

Answer 5

(1) -4x-2y=-12
(2) 4x+8y=-24

Add equations (1) and (2)
-4x +4x +-2y +8y = -12 + -24
6y = -36
Solve for y... you can do that.

Now, at this point you might be tempted to substitute... but the problem,as you stated it specified elimination...

Ok, multiply equation (1) by 4
(3) -16x - 8y = -48
Now add equations (2) and (3)
4x + -16x + 8y + -8y = -48 + -24
-12x = -72
Solve for x

Don't forget to test your answers by plugging them back into equations (1) and (2). Does
-4x - 2y = -12?
and does
4x + 8y = -24?

Answer 6

This is a nice one since you can immediately add the two equations and eliminate the x's. You just add the two left hand sides and the two right hand sides to get:

-4x +4x -2y +8y = -12 -24, or:

6y = -36, so y = -6

Substitute back to get x = 6

Answer 7

you have to eliminate a letter, lets for X

-4x-2y=-12
4x+8y=-24

-6y=-36

y=6

now, check:

plug in 6 for y into one equation:

4x+8(6)=-24
4x+48=-24
-48 -48
4x=-72
x=-18

so:

x= -18, y= 6

Answer 8

Just add the two equations to eliminate x

-4x - 2y = -12

+

4x + 8y = -24

--------------------

6y = - 36

y = -6

To solve for x by elimination, multiply the first equation by 4 then add to the 2nd equation:

-16x - 8y = -48

+

4x + 8y = -24
---------------------

-12x = -72

x = 6

Answer 9

-4x-2y=-12 /////////////////// 4x+8y=-24

the -4x and +4x eliminate echother

-2y+8y=-12 + -24
6y = -36
y=-6

plug the y into either equation to get the value of x

4x+8(-6)=-24
4x-48=-24
4x=48-24
4x=24
x=6



to check yourself plug both x and y into either or both equations

-4(6)-2(-6)=-12
-24+12=-12
-12=-12
correct answer

Answer 10

-4x-2y=-12
4x+8y=-24 to eliminate x, we add both equations
-----------------------
0x+6y=-36
6y=-36
y=-6
substitute y to eihter of the two equations:
-4x-2y=-12
-4x-(2*-6)=-12
-4x+12=-12
-4x=-12-12
-4x=-24
x=6