Using complete sentences, explain how to completely factor 2x2 − 6x − 36.

Question

anonymous · Answer

"using complete sentences" lol

anonymous · Answer

$$2x^2-6x-36$$First notice that there is a common factor of two.$$2(x^2-3x-18)$$Now we are looking for 2 numbers that add up to -3 and multiply to make -18. Namely -6 and +3$$2((x-6)(x+3$$

anonymous · Answer

I don't know why my LaTeX isn't working but, does that make sense?

anonymous · Answer

$$2((x-6)(x+3))$$

unklerhaukus · Answer

the other method is to use the quadratic formula 

$$ax^2+bx+c=0$$
$$x_{1,2}=\frac{-b\pm\sqrt{b^2-4ac}}{2a}$$
$$(x-x_1)(x-x_2)=0$$

anonymous · Answer

Ok for factoring ac=-72 and b=6 so -12 and 6 are the numbers
ac is the product and b is the sum of two numbers such that they satisfy both conditions. 
2x^2-12x+6x-36=0
2x(x-6)+6(x-6)=0
(2x+6)(x-6)=0
thus x=-3 or x=6
Hence solved