Question

Can somebody help me with number 7? Please explain as well! :)

Answer 1

To factor number 7 :
3x^2-12
3x^2+3×-4
3*1, -4:2*-2
3(x^2-2^2)
use difference of square formula ((a^2+b^2=(a+b)(a-b))
3(x+2)(x-2)