Whats 9x + 4x please show work

Question

By the way this is algebra prep.

Answer 1

If you have 9 x's and you add 4 x's to them, you will have 13 x's, so:

 

9x + 4x = 13x

 

As long as the letters are the same, just add the numbers in front of them.

Answer 2

9x + 4x = 13x

 

 

Here's why in graphic horrifying detail.

Keep in mind that multiplication can be written

with or without the star asterisk *

 

For example,   10N = 10*N

----------------------------------------------------------

 

 9x + 4x =  9*x + 4*x <--- rewrites the problem using the star asterisk for multiplication

 

               x*(9 + 4) <---- distributive property in reverse; study this step very carefully!!! It's the most important

 

              = x*(13) <---- order of mixed operations, parenthesis first

 

              = x*13 <-- don't need the parenthesis anymore; throws them away

 

              = 13*x  <--- commutative property of multiplication

 

              = 13x