Need help with algebra.....?

Question

I need a link on how to solve problems by elimination
an example problem.......
{2x- 5y= 43
{3x+4y= 28
or something like that

Answer 1

their common factor is 6
so the 1st equation 2x -5y = 43 <<<< multiply with 3
the 2nd one 3x + 4y = 28 <<< multiply with 2

so the new equation will be
6x - 15y = 129 (3rd equation)
6x + 8 y = 56 ( 4th equation)

3rd minus 4th
-15y - 8y = 129-56
-23y = 73
y = - 3 4/23

substitute y = - 3 4/23 into the 4th equation
6x = 56 - 8( -3 4/23)
6x = 81 9/23
x = 13 13/23

Answer 2

Lisa's answer is a solution by substitution, not elimination. In the elimination process, the object is to eliminate one of the variables. You do this by getting the coefficients of the variable you are eliminating to be opposite numbers. In your case, if you want to eliminate x, you need to get the coefficient of x in the first equation to be the opposite of the coeff. of x in the 2nd equat. You can do this by multiplying the 1st equat by 3 to get 6x - 15y = 129 and multiplying the 2nd equation by -2 to get -6x - 8y = -56

Now add the two equations

6x - 15y = 129
-6x - 8y = -56

-23y = 73

y = -73/23 Now substitute this value in for y in either equat. and solve for x. It would be a good idea to check your answer and see if the values work in the other equation. I get x = 312/23

Note: you don't have to eliminate x. you can eliminate y if you want to do so.

Answer 3

I 2x- 5y= 43
II 3x+4y= 28

I 2x=43+5y
x=21.5+2.5y

now you substitute x in the second equation by 21.5+2.5y:
II 3(21.5+2.5y)=28
64.5+7.5x=28
7.5x=-36.5
x=-4.866

put that back in the first equation to get y
2*(-4.866)-5y=43
-5y=52.733
y=-10.546

Answer 4

Can't you use the finger method? Cover up x to find y and do the opposite to find x. Just divide by the co efficient.