solve by the substitution method

Question

r-9s=0

9r-3s=390

 

what is the solution of the system. _ (type an ordered pair)

Answer 1

Hi George,

 

r-9s=0 so r=9s

 

substituting r=9s in eqn 9r-3s =390

 

9(9s)-3s =390

81s-3s=390

78s=390

s=390/78

s=5

 

r= 9s

r=9(5) =45

Order pair is (45,5)