Solve by the elimination method.

Question

Solve by the elimination method.

 

5r-7s=18

7r+5s=40

 

Determine the solution of the system. Select the correct choice below and, 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

Bobby,

Multiply equation 1 by 5 and equation to by 7 and that will eliminate s for you

5r-7s=18
7r+5s=40

 

25r -35s = 90
49r+35s=280    now add this two

74r = 370

r = 5

 

5(5)-7(s)=18

25-7s=18

-7s=-7

s=1

I hope this helps