Kemal G. answered • 03/28/17
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Patient and Knowledgeable Math and Science Tutor with PhD
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)
