Aroller coaster starts from a deck at an elevation of 20 feet above the ground. on the first hill it climbs 78 feet and then drops 85 feet. on the second hill the coaster climbs 103 feet and then drops 110 feet. how far below or above the deck is the coaster after the completion of the two hills?

14 feet below. the deck.

Step-by-step explanation:

That would be (20 + 78 - 85 +103 - 110 )  feet above the ground

= 6 feet above the ground.

That is 20 - 6 = 14 feet below the deck.

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