ARITHMETIC SEQUENCES HELP. (QUESTIONS ATTACHED)

Which expression do you get when you eliminate the negative exponents of 4a^2 b^216a^-3 b

Aparticular telephone number is used to receive both voice calls and fax messages. suppose that 25% of the incoming calls involve fax messages, and consider a sample of 25 incoming calls. (a) what is the expected number of calls among the 25 that involve a fax message?

If x-1 and x+3 are the factors of x3+10x2+ax+b find a and b