Hello there!
1. Okay. So 70% is positive, so it is a corresponding growth. 70% is 0.7 in decimal form. C and D are both eliminated, because that's too large. When something grows by 70%, that is less than double. 0.7 is not right either, because that's more of a decay than a growth. The only answer that makes sense id 1.70, because you are going up, and adding 1 to decimal form brings you to the decimal that when multiplied will bring you to the total. The answer is B: 1.70.
2. So, -75% is negative, so it is a decay factor. A is eliminated, because it makes no sense and B is out, because that represents growth, not decay. You lose 75% of the amount overtime compounded, but you still have 25% that remains. To find that amount, you would subtract that amount from 1 to get the decay. 1 - 0.75 is 0.25. The decay factor is 0.25. The answer is D: 0.25.
It will have 2 solutions! this is because a negative and a negative cancel each other out and will make a positive under the radical.
Initial is 12
Percent 1.05(I think but you might have to convert it)
Y=12(1.05)(5)
Y=63
We are given this
write it as the difference of cubes
use the formula for the difference of cubes
Now use the formula for the difference of squares as 
<span>If the company, hewerrtt, would like to make letter codes using all of the letters in the word hewerrtt, they would be able to make five codes. Altogether, there are eight letters in the word, but there are duplicates of the letter e, the letter r, and the letter t, so that takes out three possibilities. Three subtracted from eight is equal to five, therefore the company can make five codes using the company name.</span>
