having problems with a couple math problems?

Question

Solving for a inequality and express as an interval

21
_____ < 0

15-3x

and also express as a polynomial

(x+a) ( x^2-ax)
----------
x

The x goes under the x^2-ax portion no matter what i do i cant move it over

Answer 1

21/(15-3x) < 0
(15 - 3x)/21 < 0 (if a fraction is less than zero, it's reciprocal is also less than zero)
15 - 3x < 0 (multiply both sides by 21)
15 < 3x
5 < x

second problem
(x+a)(x^2-ax)/x = (x+a)(x-a) = x^2-a^2

Answer 2

This would be an acceptable way to write that.
(x+a) ((x²-ax)/x)

Alt 253 = ² or Alt 0178 = ²
Alt 252 = ³ or Alt 0179 = ³

Answer 3

21
_____ < 0

15-3x
12x < 0
divide by 12
x < 0

(i think)


(x+a) ( x^2-ax)


&& i dont get that. lol.