Plz help with this math problem

D. -3r^2 + 11r + 9

Step-by-step explanation:

8r + 4r^2 + 3r + 9 - 7r^2

shift somethings around so it's easier to tell

4r^2 - 7r^2 + 8r + 3r + 9

simplify/add

-3r^2 + 11r + 9

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

4y - 6 + y^2 - 9 = y^2 + 4y - 15

y^2 term

terms

- terms

total of 3 terms when simplified

step-by-step explanation: