PLZ HELP what is 5 + 5

Write the expression 7x^3-28xy^2 as the product of 3 factors

Multiply and simplify. (x - 4) (x^2 – 5x – 6) i will mark brainliest if your answer is right. show how you got the answer. if your answer is correct but does not show how you got the answer you will not be marked brainliest.

Martha is training for a duathlon, which includes biking and running. she knows that yesterday she covered a total distance of over 55.5 miles in more than than 4.5 hours of training. martha runs at a speed of 6 mph and bikes at a rate of 15.5 mph.