Question

How do you foil `(–x – 3)(3x + 20)`?

Answer 1

`(–x – 3)(3x + 20)=color(blue)(-(3x^2+29x+60)`

Explanation:

The expression is :`(-x−3)(3x +20)`

F O I L involves carrying out the below operations in the following order:

1) product of First terms :`(color(blue)(-x and 3x))`+

2)product of Outside terms:`(color(blue)(-x and 20))`+

3)product of Inside terms:`(color(blue)(-3 and 3x))`+

4)product of Last terms:`(color(blue)(-3 and 20))`

1) `-x *3x=color(blue)(-3x^2) +`

2) `-x* 20=color(blue)(-20x)+`

3) `-3 * 3x = color(blue)(-9x)+`

4) `-3 *20 = color(blue)(-60`

adding all the terms

`=color(blue)(-3x^2-20x-9x-60`
`=color(blue)(-3x^2-29x-60`
`=color(blue)(-(3x^2+29x+60)`