solve by using system of equations 6x - 10y =8 2x + 4y =7

Question

solve by using system of equations                                 6x - 10y =8                                                                         2x + 4y =7

callielovesyhuu · Answer

y=7/4+1/2x

jhannybean · Answer

For this I think the elimination method would work best.

You've got 2 equations: 6x - 10 = 8, 2x + 4 = 7

We can eliminate one variable, and solve for the other.

6x - 10 = 8
2x + 4 = 7 

First, we decide which variable would be easier to eliminate. In this case, since 6 is a multiple of 2, we can use this to our advantage. We know that in order to eliminate the 6x we need to change 2x to -6x.

jhannybean · Answer

Sorry, i forgot to add in my y's.

6x - 10y = 8
2x + 4y = 7 *

jhannybean · Answer

How would we do this? We multiply the entire second equation by -3.

-3(2x + 4y = 7)

this gives us -6x -12y = -21 

Using this derived equation, we can eliminate the x's.

    6x - 10y = 8
  -6x -12y = -21
---------------
     0  - (10+12)y = 8-21

With this we have our equation for y.

-22y = -13

y =  -13/ -21

y =  13/21

jhannybean · Answer

Now we use our value of y and substitute it into one of the given equations to find x. 

Let's take the second one for example. 

When y = 13/21, 

2x + 4(13/21) = 7    distribute

2x + (4 * 13)/21 = 7

2x + 52/21 = 7             keep all the x's on one side and all your constants on the other.

2x =  7 - (52/21)

2x = 95/21

x = (95/21)/2

x = 95/42