How do I Factor 125x^3 -64 The answer is not (5x+4)(5x-4) or (5x-4)(25x^2 +15x+16)

Mathematics

1 answer:

pychu [463]3 years ago

8 0

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).

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Answer:

a . See attachment

b. because we will find the distance from the bottom of the ladder to the base of the building.

c. sin 60 = opposite side / hypotenuse

d.sin 60 = x / 10

e . 8.66 ft =x

f. see attachment

i. cos 60° = adjacent side / hypotenuse

Step-by-step explanation:

a . See attachment

b. because cos 60° = adjacent side / hypotenuse, the hypotenuse is equal to the length of the ladder (10), and the adjacent side that we will find is the distance from the bottom of the ladder to the base of the building. not the height that the ladder reaches .

c. sin 60 = opposite side / hypotenuse

Because we will find the opposite side which is the height that the ladder reaches.

d.sin 60 = x / 10

e .

0.866025403 = x/10

10 (0.866025403) =x

8.66 ft =x

f. see attachment

i. cos 60° = adjacent side / hypotenuse

Because we will find the adjacent side which is the distance from the bottom of the ladder to the base of the building.