Active 5
6
7
8
9
10
TIME REMARANG
31:09
A number, y, is equal to the difference of a larger number and 3. The same number is one-third of the sum of the larger
number and 9. Which equations represent the situation?
x+y = 3 and x-3y=-27
Ox+y = 3 and x-3y --9
O x-y-3 and x-3y=-27
x-y-3 and x-3y --9

1/6

step-by-step explanation:

hello from mrbilldoesmath!

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

discussion:

in general, the factorization of a^3 + b^3 is

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

in our case note that 343 = 7^3 and 216 = 6^3 so the equation becomes:

343x^3 + 216y^3 = (7x)^3 + (6y)^3

if you think of a (above) as 7x and b as 6y the factorization becomes

343x^3 + 216y^3 =

((7x + 6y) (   (7x)^2 - 7x*6y + (6y)^2)   =

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

you,

mrb

(a + b) (a^2 - a b + b^2)

the formula of a midpoint between a abd b: