x^2+9 and a^2-100?

Question

I need these two factored quickly please :O

x^2+9 and a^2-100

it's like a square and a cube so their confusing me and i have to go test in an hour

5 stars to whoever gets it first

Answer 1

a² - 100 = (a + 10)(a - 10)
x² + 9 doesn't factor over the reals, but
x² + 9 = (x + 3i)(x - 3i)

where's the cube you mentioned?

Answer 2

OK

x^2 + 9

Results are irrational (+- 3i)
Cannot be factored unless as follows;
(x-3i)(x+3i)
==============

a^2 - 100
(a-10)(a+10)

Hope that helps.