Factor completely.

5x 2 + 10x - 40

(x + 4)(x - 2)

Step-by-step explanation:

For factoring when there's a coefficient on the leading variable, I use the "slip n' slide" method (my teacher called it that, I had no part in naming it), but when that fails, you can use the quadratic formula.

First, you "slip" the leading coefficient to the end, and multiply.

5x² + 10x - 40

x² + 10x - 200

Now, you factor it normally.

x² + 10x - 200

= (x + 20)(x - 10)

Then, you divide the 2nd part in each parentheses with the coefficient you slipped in the beginning. This is super important! I always had trouble remembering this step, so hopefully you won't.

(x + 20/5)(x - 10/5)

= (x + 4)(x - 2)

I hope this helped!

then, the surface area of the sphere shown in the image is: 256π sq. units!

step-by-step explanation:

the lateral surface area of a sphere is 2πrh where h=2r.

then:

surface area = 4πr^2.

in this case, r=8 units ⇒ surface area = 4π(8 units)^2. = 256π sq. units!

then, the surface area of the sphere shown in the image is: 256π sq. units!