Step 1: Make sure that the trinomial is written in the correct order; the trinomial must be written in descending order from highest power to lowest power.
Step 2 : Decide if the three terms have anything in common, called the greatest common factor or GCF. If so, factor out the GCF. Do not forget to include the GCF as part of your final answer.
Step 3 : Multiply the leading coefficient and the constant, that is multiply the first and last numbers together.
Step 4 : List all of the factors from Step 3 and decide which combination of numbers will combine to get the number next to x.
Step 5 : After choosing the correct pair of numbers, you must give each number a sign so that when they are combined they will equal the number next to x and also multiply to equal the number found in Step 3.
Step 6 : Rewrite the original problem with four terms by splitting the middle term into the two numbers chosen in step 5.
Step 7 : Now that the problem is written with four terms, you can factor by grouping.
To answer this problem, one way is to use the calculator and add directly the two numbers and get the average between the two. The answer is 25/77. We can also get this number by getting the LCM of the denominators which is 77. 2/7 is equal to 22/77 while 4/11 is equal to 28/77. 0.5*(22 +28) is equal to 25. Hence the answer is 25/77.
The second term of the given sequence aₙ = -5(n² + 1n) when solved gives us; a₂ = -20
<h3>How to find the nth term of a sequence?</h3>
We are given the formula for a sequence as;
aₙ = -5(n² + 1n)
Where n is the position of the term.
Now, for the first term, we will have;
a₁ = -5(1² + 1(1))
a₁ = -10
The second term of the sequence is;
a₂ = -5(2² + 1(2))
a₂ = -20
Read more about Sequence at; brainly.com/question/6561461
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Given:
cos 120°
To find:
The exact value of cos 120° in simplest form with a rational denominator.
Solution:
We have,

It can be written as

![[\because \cos (90^\circ-\theta)=-\sin \theta]](https://tex.z-dn.net/?f=%5B%5Cbecause%20%5Ccos%20%2890%5E%5Ccirc-%5Ctheta%29%3D-%5Csin%20%5Ctheta%5D)
![[\because \sin 30^\circ=\dfrac{1}{2}]](https://tex.z-dn.net/?f=%5B%5Cbecause%20%5Csin%2030%5E%5Ccirc%3D%5Cdfrac%7B1%7D%7B2%7D%5D)

Therefore, the exact value of cos 120° is
.