solve the system by addition?

Question

2x- 4y= 7, 4x + 2y = 9

Answer 1

Double the second equation.

2x-4y=7
8x+4y=18 Add the equations.
10x = 25
x = 2.5

5-4y=7
12=4y
3=y

Answer 2

As the two equations are equal, There sums would also be equal. {such as 5= 5 & 7 = 7 or 5 + 7 = 5 + 7.}

Therefore, (2x - 4y) + (4x + 2y) = 7 + 9 = (now here, there cannot be any result as even if they are added, x and y would be there. So, we multiply the second equation by 2 {5 + 2 * 7 = 5 + 2 * 7)
(2x - 4y) + 2(4x + 2y) = 7 + 2(9) =
2x - 4y + 8x + 4y = 7 + 18 =
10x = 25 =
x = 25/10


Now, to find the value of y-
2x - 4y = 7 =
2(25/10) - 4y = 7
5 - 4y = 7 =
- 4y = 7 - 5 =
-4y = 2 =
y = 2/-4 =
y = -2/4

Answer 3

First, multiply the second equation by 2
2(4x + 2y =9)
8x + 4y = 18
Now add the result to the first equation
8x + 4y = 18
2x - 4y = 7

The result is
10x = 25
x = 2.5

Then plug in x into one of the equations and solve for y.
2(2.5) - 4y = 7
5 - 4y = 7
-4y = 7 - 5
-4y = 2
y = -0.5

Answer 4

2x-4y=7 multiply both sides by 2 4x - 8y = 14
now subtract second equation (-)4x+2y=9
Answer - 10y=5 y=-2
Now solve for x 2x+8=7 2x= -1 x= - 1/2 ( -1/2,-2 )

Answer 5

quite you're meant to function the two equations at the same time. in case you seem how they are coated up, you upload down the columns from suitable to left purely such as you may do in case you extra customary numbers. as a result, 6 + 2 = 8 y + -y = 0 and x = x = 2x. you're left with 2x + 0 = 8. The 0 is purely a placeholder. you're quite left with 2x = 8. 2x quite means 2 situations x. branch undoes multiplication so which you divide the two facets via 2. you're left with x = 4. you could now plug x into the two equation to clean up for y.

Answer 6

2x-4y=7
4x+2y=9 multiply by 2

Therefore.......
2x-4y=7
8x+4y=18
--------------
10x=25
x=25/10

y=
2x-4y=7
Therefore..........
2*25/10-4y=7
5-4y=7
-4y=7-5
-4y=2
Therefore....
y=2/-4
=1/-2


x=2.5,y=-0.5