2x^4-7x^3-29x^2-8x+12=0 with roots of -2 and 6

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

Car a and car b were in a race .the driver of car b claimed that his car was twice as fast as car a

1. according to the internal revenue service, the mean tax refund for the year 2007 was $2,708. assume the standard deviation is $650 and that the amounts refunded follow a normal probability distribution. a. what percent of the refunds are more than $3,000? b. what percent of the refunds are more than $3,000 but less than $4,000? c. what percent of the refunds are less than $2,000?