Which of the following is a valid conclusion for the problem x2 + 6x + 8 = 0?

x = -2 or x = -4

Step-by-step explanation:

Step 1 : Middle term break

x^2 + 6x + 8 = 0

x^2 + 4x + 2x + 8 = 0 (4+2 is equal to six and 4x2 is equal to  8)

x(x + 4) + 2(x +4)

(x+2) (x+4)

x= -2 or x= -4

!!

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)