Chris is mailing his friend a poster that has been rolled up in a long tube. He has a box that measures 20 inches by 8 inches by 4 inches. What is the maximum length the rolled poster can
be?

the answer is a

step-by-step explanation:

understand that i don't know the answers

will someone answer his question

answer:   x = 3 + √11     and     x = 3 - √11

step-by-step explanation:

x² - 6x + 9 = 11

(x - 3)² = 11

x - 3 = ±√11

    x = 3 ± √11

x = 3 + √11     and     x = 3 - √11