Question

Find the solution of the following system using Gauss elimination. (Enter your answers as a comma-separated list.)

-18x	+	2y	=	6
-15x	−	5y	=	-15

(x, y) = (  )

Answer 1

(0,3)

Multiply the first equation by 5,and multiply the second equation by 2.

5(−18x+2y=6)

2(−15x−5y=−15)

Becomes:

−90x+10y=30

−30x−10y=−30

Add these equations to eliminate y:

−120x=0

Then solve−120x=0for x:

−120x=0

−120x−120=0−120(Divide both sides by -120)

x=0

Now that we've found x let's plug it back in to solve for y.

Write down an original equation:

−18x+2y=6

Substitute0forxin−18x+2y=6:

(−18)(0)+2y=6

2y=6(Simplify both sides of the equation)

2y/2=6/2(Divide both sides by 2)

y=3

x=0and y=3