Collect like terms
-2x is the answer
Answer:
K = 
Step-by-step explanation:
P = KTV
Divide both sides by TV
(P/TV) = K
Let rs.5 denominations be x , then rs 10 denominations will be 90-x
then total amount 5x + 10(90-x) which is rs.500
5x + 10(90-x) = 500
900 - 5x = 500
400 = 5x
therefore x = 80
therefore no. of rs.5 is 80
no. of rs.10 is 90-x = 90-80 = 10