(3a-2b)(3a+3b) so this is foil but i always get messed up on it does anyone now how to do it

9a^2 +  3ab  - 6b^2

Step-by-step explanation:

(3a-2b)(3a+3b)

First term of each grouping is 3a and 3a.

Multiply those you get 9a^2.

Outer term of each grouping is 3a and 3b.

Multiply those you get 9ab.

Inner term of each grouping is -2b and 3a.

Multiply those you get -6ab.

Last term of each grouping is -2b and 3b.

Multiply those you get -6b^2.

Add up all your products from above.

9a^2+9ab+-6ab+-6b^2

There are like terms here.  The 9ab+-6ab which is 3ab.

So you can write your expression now as:

9a^2 + 3ab  +-6b^2

9a^2 +  3ab  - 6b^2

Step-by-step explanation:

80π/3 or about 83.775

step-by-step explanation:

since a cone is 1/3 of a cylinder, we need to find the base's area. since area = πr^2, we get 16π. then, multiplying this by 5, we get 80π. dividing by 3, since the cone's volume is 1/3 of that of a cylinder's, we get 80π/3.

hope this !