12.
Add like terms from both trinomials:



Combine these terms to get a new trinomial as your answer:

13.
Subtract like terms from both trinomials (note that subtracting a negative is the same as adding it as a positive):



0 can be left out of the answer.
Combine these terms to get a binomial as your answer:
We can see the sequence goes by decreasing 9 on each number
so the numbers are
2, -7, -16, -25, -34, -43, -52, -61, -70
so adding all these numbers we get
2-7-16-25-34-43-52-61-70
= -306
hope this helped
<span> 0.8 that for the 44/55 idk what u want me to do with the 39
here how 2 turn them into decimals
</span>
The fraction bar means "divided by." So finding the decimal equivalent of a fraction such as 1/4 means 1 divided by 4.
1 ÷ 4 = 0.25
It is not necessary to reduce a fraction before you convert it to a decimal but doing so might make the long division easier if you are doing it by hand.
For example, 9/12 = 9 ÷ 12 = 0.75. If you solve this with a calculator then it is easy to get the answer. However, if you use long division to solve this problem by hand or in your head, reducing 9/12 = 3/4, may make the problem easier. You may even recognize that 3/4 = 0.75 because 3 quarters equals 75 cents.
cited from -http://www.calculatorsoup.com/calculators/math/fraction-to-decimal-calculator.php