Multiply.

(2.1×102)×(3.5×105)

Y=4x^2+x-1 solve using quadratic formula

For how answer my question this will be the last question can you answer in math subject

The first-serve percentage of a tennis player in a match is normally distributed with a standard deviation of 4.3%. if a sample of 15 random matches of the player is taken, the mean first-serve percentage is found to be 26.4%. what is the margin of error of the sample mean? a. 0.086% b. 0.533% c. 1.11% d. 2.22%