The rules are


Let me show you why with a couple of examples: suppose we want to multiply

Since powers are just repeated multiplications, we have

Similarly, we have

If the term in the middle is 16x^2
6x^2-24x-16x^2-9x+1 =
-10x^2-33x+1
Answer: In the figure AB is about 8.4 inches and AC is about 13.05 inches.
Step-by-step explanation: We can use cosine to find the hypotenuse. 
Using a calculator x is about 13.05
Using tangent we can find the length opposite of <C

Using a calculator x would be about 8.4
Answer: 9
Step-by-step explanation: just devide then times
239.99 x 75%(75/100) ~ $180
$180 x 90%(90/100) = $162