Home->ACT Math

Which of the following correctly factors the expression 25x⁴ - 16y⁸?

(F) (25 - 16)(x² - y⁴)(x² + y⁴)

(G) (5x² - 4y⁴)(5x² + 4y⁴)

(H) (25x² - y⁴)(x² + 16y⁴)

(J) (5x⁴ - 4y⁸)(5x⁴ + 4y⁸)

(K) (5x⁴ - 8y⁸)(5x⁴ + 2y⁸)

A science tutor charges $60 an hour to help students with biology homework. She also charges a flat fee of $40 to cover her transportation costs. How many hours of tutoring are included in a session that costs $220?

（A）2 （B） 3 （C） 3 （D） 4 （E）

Correct Answer: B

When written in symbols, "The square of the product of a and b" is represented as:

(F) ab (G) ab² (H) (ab)² (J) a²b (K) (a²b²)²

Correct Answer: H

Stacie has a bag of solid colored jellybeans. Each jellybean is orange, purple, or pink. If she randomly selects a jellybean from the bag, the probability that the jellybean is orange is , and the probability that it is purple is . If there are 72 jellybeans in the bag, how many pink jellybeans are in the bag?

（A）16 （B） 24 （C） 32 （D） 40 （E） 48

Correct Answer: C