Question

Completely the factor -3x²-6x+45

Answer 1

Let's factor:

Taking -3 common:

`\begin{gathered} -3x^2-6x+45 \\ -3(x^2+2x-15) \end{gathered}`

Now, think of two numbers, when multiplied gives you -15 and when added gives you +2.

It's +5 and -3

So now we can factor:

`\begin{gathered} -3(x^2+5x-3x-15) \\ -3(x(x+5)-3(x+5)) \\ -3(x+5)(x-3) \end{gathered}`