Question

Can someone help me with this? My teacher said its a must in the homework and i cant find a solution.

Answer 1

`8x^3+28x^2-16x`

Explanation:

Volume of rectangular prism:
`l*b*h` (l = length, b = breadth, h = height.)

Volume of rectangular prism:

`(x+4)*(2x-1)*4x`

`4x\left(x+4\right)\left(2x-1\right)`

Expand the two brackets using FOIL:

`4x(x* \:2x+x\left(-1\right)+4* \:2x+4\left(-1\right))`

`4x\left(2x^2+7x-4\right)`

Expand:

`4x* \:2x^2+4x* \:7x+4x\left(-4\right)`

`8x^3+28x^2-16x`