Let r varies inversely as u, and r = 8 when u =5. Find r if u=55

Step-by-step explanation:

Given that, r varies inversely with u. r=k÷u, k being the constant.

Therefore, k=8×5, ( after making k the subject of your formula).

This implies that k=40.

Now, according to the formula r=k÷u,

r=40÷55

Therefore, r=0.72

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

answer: your answer is c

step-by-step explanation: