Please solve this System of Equation

Question

2x-9y=8

-5x+8y=-20

Answer 1

Hi Jaela,

 

We will try to eliminate one of the variables. To do this, we need to multiply the equations.

 

I will eliminate x so I will multiply the first equation by 5 and the second one by 2. This way, the xs will cancel when summed.

5*(2x-9y=8)

2*(-5x+8y=-20)

 

10x - 45y = 40

-10x + 16y = -40

__________________ (addition bar)

0 - 29y  = 0

y = 0

 

2x - 9y = 8 (plugged in y=0 to solve for x in the first equation)

2x - 9*(0) = 8

2x = 8

x = 4

 

Let's check by plugging in the values in the second equation.

-5*(4) + 8*(0) = -20 (true)