Which could be the first step of an indirect proof of the conditional below? Select all that apply. If x = 4, then 4x = x2.

A. If 4x ≠ x2, then x ≠ 4.
B. If x = 4, then 4x = x2.
C. Assume if 4x ≠ x2, then x ≠ 4.
D. Assume if x ≠ 4, then 4x ≠ x2.

The number of revolutions of two pulleys is inversely proportional to their diameters. if a 24-inch diameter pulley making 400 revolutions per minute is belted to an 8-inch diameter pulley, find the number of revolutions per minute of the smaller pulley.

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

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