# How do you factor #3x^2 + 5#?

##### 1 Answer

Jun 22, 2016

#### Explanation:

Note that if

Hence

So this quadratic has no Real zeros and no linear factors with Real coefficients.

It can be factored with Complex numbers.

Use the difference of squares identity:

#a^2-b^2 = (a-b)(a+b)#

with

#3x^2+5=(sqrt(3)x)^2-(sqrt(5)i)^2#

#=(sqrt(3)x-sqrt(5)i)(sqrt(3)x+sqrt(5)i)#