Which expression is equivalent to 9x2 − 16

Two planes leave an airport at the same time, one flying east, the other flying west. the eastbound plane travels 20 mph slower. they are 1600 mi apart after 2 hr. find the speed of each plane.

The polynomial 10x3 + 35x2 - 4x - 14 is factored by grouping. 10x3 + 35x2 - 4x - 14 5x )-20 what is the common factor that is missing from both sets of parentheses?

On #16 : explain how factoring a trinomial, ax^2+ bx+ c, when a does not equal 1 different from factoring a trinomial when a = 1.