How do i factor 125x^3 -64 the answer is not (5x+4)(5x-4) or (5x-4)(25x^2 +15x+16)

The correct factorization would be (5x - 4)(25x^2 + 20x + 16).

The law of factoring cubes states that we use the following formula when we have two cubes being subtracted by one another.

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

If we take the cube root of 125x^3 we get 5x, which will be our a value. If we take the cube root of 64, we get 4, which will be our b value. Then we plug in to the formula.

(5x - 4)((5x)^2 + (5x)(4) + 4^2)

(5x - 4)(25x^2 + 20x + 16)

I think the problem with your second answer is that you just did not properly multiply the 5x and the 4 to get 20x (instead you got 15x).

the answer is y < -3 or   y > 3

-3y > 7 + 2

-3 y > 9

y < -3

54 kilometers per hour

step-by-step explanation:

according to rules:

1 km = 1000 meter

which means that 1 meter = 1/1000 km

1 hour = 3600 second [ as 1 hour = 60 min = 60 *60 seconds ]

which means that 1 second = 1/3600 hour

therefore, 1 kilometer/hour =

thus to convert 15 meter per second to kilometer per hour, we multiply 15 to 3.6 kilometer/hour.

15 meter/second=   which is the required answer.