JoAnn covered a square wall using 84.5 square feet of wallpaper. What whole number of feet is the closest to the height of the wall?

height ≈ 9 feet

Step-by-step explanation:

the wall is a square, so the length and width are equal

l • w = area

l • w = 84.5

l = w

l = √84.5

= 9.19238815543

≈ 9 feet

hello from mrbilldoesmath!

answer:

(7 x + 6 y) (49 x^2 - 42 x y + 36 y^2)

discussion:

the trick is to recognize that 343 = 7^3 and 216 = 6^3 and, in general,

a^3 + b^3 =   (a + b) (a^2 - a b + b^2).

in our case

343x^3+216y^3   =   (7x)^3 + (6y)^3

so take a = 7x and b = 6y in the above equation to get the answer.

you,

mrb