(3x-6)(3x+6)

Question

please help me with this problem

Answer 1

Looking at the expressions, they are of the form (a - b) (a + b) . This is simply difference of two squares

such that the answer would be a²- b², therefore (3x-6)(3x+6) = (3x)²-(6)² = 9x² - 36

Proof:

Expand the form  ( a -b)(a + b) = a² + a b - b a - b² = a² - b²      as  + a b and - b a cancel each other out

Answer 2

Using the foil technique to multiply....

 

First          inside      outside      last

(3x  X 3x) +(3x X 6) +(-6 X 3x) + (-6 X 6)

9x^2+ 18x - 18x - 36

Answer: 9x^2 -36

Answer 3

If we use the FOIL method we obtain:

First-(3x)(3x)=9x²

Outer-(3x)( 6)=18x

Inner-(-6)(3x)=-18x

Last-(-6)(+6)=-36

Now we can combine like terms and we end up getting:

9x²+18x-18x-36

so 9x²-36

Answer 4

To solve this problem, we will use the FOIL Method.  This will be used to multiply the two linear functions into one quadratic.  First, we will multiply the First terms.  In this case, the first terms are 3x and 3x.  3x*3x=9x^2.  Then we multiply the Outside terms, which are 3x and 6, so 3x*6=18x.  After that, we multiply the Inside terms, or 3x and -6 so 3x*-6=-18x and last, we multiply the Last terms, which are 6 and -6. 6*-6=-36.  So now we have 9x^2+18x-18x-36.  The last thing we do is to combine like terms, so 18x and -18x go away, leaving 9x^2-36 as our answer.