Question

solve the system of equations
5x+2y=11 3x-4y=4 give answer as decimal if required. any help would be appreciated, thank you

Answer 1

multiply the top equation by 2 and you have

10x+4y = 22
3x-4y = 4

now add, and the y's go away, leaving

13x = 26

Now you can find x, then y.

Answer 2

still having trouble getting y. why multiply top by 2. first time doing this, sorry thanks for the help

Answer 3

this is called elimination. You try to make one variable disappear, then you can find the other one.

Since one equation had 2y and the other had 4y, you multiply one by 2, so you get 4y in both equations. Then when you add 4y and -4y, you get

13x + 0y = 26

and y is gone. Now x=2, and you can use either equation to find y:

5*2+2y=11 so y = 1/2
or
3*2-4y=4 so y = 1/2

You can also use substitution. Rearranging the 1st equation gives

2y = 11-5x

Since 4 = 2*2, you can plug that into the 2nd equation to have

3x-2(11-5x) = 4
3x-22+10x = 4
13x = 26
x=2
as before.

Answer 4

steve, thank you so much for explaining this. I get it now.