Which set of numbers may represent the lengths of the sides of a triangle?

A.
5, 7, 9
C.
8, 5, 3
B.
1, 3, 4

D.
4, 4, 9

A

Step-by-step explanation:

because for the sides to make a triangle the sum of the two shorter sides must be greater than the longest

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