Question

What is the product of (3x + 1)(3x – 4)?
Step by step.

Answer 1

9x^2 - 9x - 4

Explanation:

(3x + 1)(3x – 4)

Here you can use the FOIL method (FOIL stands for: First, Outer, Inner and Last)

First you multiply 3x by 3x since these are the First inside both binomials.

3x * 3x = 9x^2

Then you multiply 3x by -4 since these are the Outer inside both binomials.

3x * -4 = -12x

Then you multiply 1 by 3x since these are the Inner inside both binomials.

1 * 3x = 3x

Then you multiply 1 by -4 since these are the Outer inside both binomials.

1 * -4 = -4

And finally add everything together:

9x^2 + (-12x) + 3x + (-4)

Since adding a negative number is the same as subtracting it:

9x^2 - 12x + 3x - 4

We can now simplify this a little by adding all the x's together:

9x^2 - (12x + 3x) - 4 =

9x^2 - 9x - 4

Hope I could help you understand!

If you still wonder anything, don't hesitate to ask in the comments below!

Have a wonderful day! (●'◡'●)

Answer 2

9x^2-9x-3

Explanation:

3x*3x=9x^2

3x*-4=-12x

1*3x=3x

1*-4=-3

9x^2-12x+3x-3

9x^2-9x-3