Use a calculator to find the value of the trigonometric expression to four decimal place cos 50

In the polynomial below, what number should replace the question mark to produce a difference of squares? x2 + ? x - 36

Asurvey of 2,000 doctors showed that an average of 3 out of 5 doctors use brand x aspirin.how many doctors use brand x aspirin

Square a has a side length of (2x-7) and square b has a side length of (-4x+18). how much bigger is the perimeter of square b than square a?and show all work! you so