Answer:
See below
Step-by-step explanation:
She combined 3x and - 9x incorrectly
she should have gotten - 6 x not - 12 x
.05 is equal to 5%
So for every dollar the mark up is .05cents
So if you times $81 by .05 this will give you the mark up because each of the 81$ needs .05 added to it.
So $4.05 Is the mark up
And
The cost would be markup and original added together
