When submitting an answer in the form of an exponent, use a caret (^) to indicate the power. For example, 53 would be written as 5^3.

Factor each expression.
1. 216x3 – 1 (1 point)

2. 8x3 + 125 (1 point)

3. x4 – 5x2 + 4 (1 point)

Question

When submitting an answer in the form of an exponent, use a caret (^) to indicate the power. For example, 53 would be written as 5^3.

Factor each expression.
1.   216x3 – 1  (1 point)

2.   8x3 + 125  (1 point)

3.   x4 – 5x2 + 4  (1 point)

anonymous · Answer

it turns out that $216=6^3$ so the first one is the difference of two cubes 
$$(6x)^3-1^3$$ use 
$$a^3-b^3=(a-b)(a^2+ab+b^2)$$ with 
$a=6x$ and $b=1$

perl · Answer

Prove that if there is an injection f : A -> A which is not surjective, then A is not a finite set.

perl · Answer

satellite, maybe you can help me

perl · Answer

i have heard you are a math genius

anonymous · Answer

similarly, the second one is the sum of two cubes, 
$$(2x)^3+5^3$$ this time use 
$$a^3+b^3=(a+b)(a^2-ab+b^2)$$ with 
$$a=2x,b-5$$

anonymous · Answer

@perl post an i will see what we can do

perl · Answer

ok :)

perl · Answer

satellite, you do statistics?

anonymous · Answer

thank you sattelite