Find the domain of the expression:
1. 6x^2-9, x0
2. (x^2-x-12)/(x^2-8+16)
Please show steps or explain them to me! Thank you!

Question

Find the domain of the expression:
1. 6x^2-9, x>0
2. (x^2-x-12)/(x^2-8+16)
Please show steps or explain them to me! Thank you!

anonymous · Answer

-9

anonymous · Answer

is it like all real numbers, or can you please explain?

anonymous · Answer

yes

anonymous · Answer

it still does not make sense, x has to be > 0

anonymous · Answer

the   real numer  has  negive

anonymous · Answer

@jim_thompson5910 can you help me with these two problems?

jim_thompson5910 · Answer

by default, all polynomials have a domain of the set of all real numbers

jim_thompson5910 · Answer

but because it clearly states that x > 0, that means the domain is x > 0, so the domain is the set of positive real numbers

jim_thompson5910 · Answer

to find the domain of (x^2-x-12)/(x^2-8x+16), set the denominator equal to zero and solve for x

those two solutions will be values you exclude from the domain

anonymous · Answer

Thank you! Now my answers are:
1. x=all + real numbers
2. x cannot=+ or - 4, and -2
is that right?

jim_thompson5910 · Answer

the first one is correct, but the second is not

jim_thompson5910 · Answer

hint: x^2 - 8x + 16 factors to (x-4)(x-4)

anonymous · Answer

so x cannot equal 4, or -2 ?

jim_thompson5910 · Answer

how are you getting -2?

anonymous · Answer

oh nevermind I see what I was doing wrong,  was separating x^2 and -8x and solving them each for -16 separately. So the answer is just x cannot = 4 ?

jim_thompson5910 · Answer

bingo, the domain is the set of all real numbers but x cannot equal 4

anonymous · Answer

Okay thank you! :)

jim_thompson5910 · Answer

you're welcome