Question

Plz help me how would you solve 4x + 2y = 18, 3x - 5y =20 by elemination

Answer 1

Answer: x = 5, y = -1

Step-by-step explanation:

Equation 1: 4x + 2y = 18

Equation 2: 3x - 5y = 20

In order to eliminate one of the variables , find the LCM of either x or y.

I chose to eliminate y.  The LCM of 2 & 5 is 10.

Multiply the entire equation so the coefficient of the variable equals the LCM.

Then add the equations and solve for the remaining variable.

5(4x + 2y = 18)       -->        20x + 10y = 90

2(3x - 5y = 20)      -->           6x  - 10y = 40

                                           26x          = 130  

                                          ÷26            ÷26

                                                x         =  5

Next, input x = 5 into either of the equations to solve for y.

Equation 1: 4x + 2y = 18

                 4(5) + 2y = 18

                  20  + 2y = 18

                -20            -20

                           2y = -2

                          ÷2     ÷2

                             y = -1