-7x + 4y = -6 and 2x - 5y = 21 multi with elimination method

Question

need help!!

Answer 1

The system of equations are -7x + 4y = -6 and 2x - 5y = 21

Step - 1:

Multiply two equations by a constants to get two equations that contain opposite terms.

-7x +  4y = -6  (Multiply by 2)  - 14x + 8y = - 12

 2x - 5y = 21   (Multiply by 7)  14x - 35y = 147

Step - 2:

Add the equations, to elimiinate x variable.

- 14x + 8y = - 12

  14x - 35y = 147

____________________

         - 27y = 135

             y = 135/27

              y = - 5

Step - 3:

Subtitute the value in any one of the equations to solve other variable.

2x - 5(- 5) = 21

2x + 25 = 21

2x = - 4

x = - 2

The solution x = - 2 and y = - 5

Comments

Great way to do this problem