Solve using the elimination method

Question

Solve using the elimination method.

 

-4.5x+7.5y=9

 

-x+1.5y=5

 

Determine the solution of the system. Select the correct choice belowand, if necessary, fill in the answer box to complete your choice.

 

A. __(Type an ordered pair)

B. There are infinitely many solutions.

C. There is no solution.

Answer 1

First, express x in terms of y

 

-x+1.5y=5

-x=5-1.5y

x=1.5y-5

 

Then plug this value of x into the other equation and solve for y

 

-4.5(1.5y-5)+7.5y=9

 

-6.75y+22.5+7.5y=9

 

.75y=-13.5

 

y=-13.5/.75=-18

 

if y=-18, then x=1.5(-18)-5=-32

 

(x,y)=(-32,-18)