Question

NEED HELP!! Jimmy is trying to figure out how many pennies are in his bank. He asked his mother to help him figure out the total. He tells her to let the amount in the bank equal 21X^3+18X^2+9X and each penny equal 3x. Can you help them figure out how many pennies are in the bank? A.7X^2+6X+3 B.21X^2+18X+9 C.7X^4+6X^3+3X D.21X^4+18X^3+9

Answer 1

Factor out 3x. In other words, divide each term by 3x.

21x^3 + 18x^2 + 9x

Note: instead of dividing by 3x you can split it up; divide by 3 and then divide by x.

21x^3 / 3 = 7x^3
7x^3 / x = 7x^2

18x^2 / 3 = 6x^2
6x^2 / x = 6x

9x / 3 = 3x
3x / x = 3

A. 7x^2 + 6x + 3