3X^2+15X+12

Question

DONT UNDERSTAND!

Answer 1

Ok, you can factor in various ways but I'll use the quadratic formula.

 

(-b ± square root ((b^2)-4ac)) / 2a

 

a = 3

b = 15

c = 12

 

(-15 ± square root ((15^2)-4(3)(12))) / 2(3)

 

(-15± sqaure root (81)) / 6

(-15 ± 9)/6

So it's x = (-15 +9)/6 and (-15-9)/6

 

x = -1, -4

If you want it in factored form it's

(x +1)(x+4)

 

Answer 2

Hi Hannah,

 

3x² +15x +12

 

=3(x² +5x + 4)

 

= 3(x² +4x +1x +4)

 

= 3{ x(x+4) +1(x+4)}

 

= 3(x+4)(x+1)