(6.0x10^5)x(3.0x10^4)=?

18x10^20
18x10^9
1.8x10^20
1.8x10^10

If f(x)=x^3 and g(x)=2x+7 when g(x)=-5

Acoin bank containing only dimes and quarters has 12 more dimes than quarters. the total value of the coins is $11. how many quarters and dimes are in the coin bank?

0if x and y vary inversely and y=6 as x=7, what is the constant of variation?