Algebra 2 Help

[xxkryptic]

Hey I would like to double check some of my answers with those of you who know the topic much better than I do. This thread will grow as I go through more and more of the subject this week ;p numbers added in their own parenthesis are exponents.

Simplify the given expression

Question My answer

1) 18x (10xy^18) (-6x^-5(y^4) = (180x²y^18) (-108x^-4y^4)

2) 63x²-2x-1 = (7x-1) (9x+1)

3) 54x³-90x²+33x-55 = Unknown how to solve

4) 8m³-125 = (8m-5)(8m²+40m-5²)

5) -7xy(xy³-2xy+6y²) = 84x³y^6

 

[Determinate]

1) 18x (10xy(18)) (-6x(-5)y(4)) = (180x²y(18)) (-108x(-4)y(4))

Don't understand your notation? Maybe use a carat (^) to denote exponents instead?

2) 63x²-2x-1 = (7x-1) (9x+1)

This one is correct.

3) 54x³-90x²+33x-55 = Unknown how to solve

Don't remember atm, I'd have to look it up/grab a calculator.

4) 8m³-125 = (8m-5)(8m²+40m-5²)

Incorrect.
Correct would be:
(2m - 5)(4x² + 10x + 25), because 8 = 2³

5) -7xy(xy³-2xy+6y²) = 84x³y(6)

Wrong. You didn't distribute properly.
Correct would be:
-7x²y^(4) + 14x²y² - 42xy³

 

[Phatz_Owner]

54x³-90x²+33x-55 = Unknown how to solve

x³-x² = x.
So
54x-90x+33x-55.
= -36x+33x-55
= -3x-55

 

[rages]

3) 54x³-90x²+33x-55 = Unknown how to solve

>>54x^3 - 90x^2 + 33x - 55
>>18x^2(3x-5) + 11(3x - 5)
>>(3x - 5)(18x^2 + 11)

Have fun.

 

[Jimmy]

x³-x² = x

No, no, no.

x² = x * x
x³ = x * x * x

(x * x * x) - (x * x) ≠ x

 

[SuF]

No, no, no.

x² = x * x
x³ = x * x * x

(x * x * x) - (x * x) ≠ x

In numbers:

4 = 2 * 2
8 = 2 * 2 * 2

8 - 4 = 4

4 ≠ 2

 

[kayosman]

No, no, no.

x² = x * x
x³ = x * x * x

(x * x * x) - (x * x) ≠ x

x^3 - x^2 = x^1 = 1? I think.

EDIT: Disregard that, it's / not -.