Answer:
Third option is the right choice.
Step-by-step explanation:
Manipulate the right hand side.
![\sec \left(x\right)\\\\=\frac{1}{\cos \left(x\right)}\\\\\mathrm{Use\:the\:following\:identity}:\quad \:1=\cos ^2\left(x\right)+\sin ^2\left(x\right)\\\\=\frac{\cos ^2\left(x\right)+\sin ^2\left(x\right)}{\cos \left(x\right)}\\\\\Rightarrow \mathrm{True}](https://tex.z-dn.net/?f=%5Csec%20%5Cleft%28x%5Cright%29%5C%5C%5C%5C%3D%5Cfrac%7B1%7D%7B%5Ccos%20%5Cleft%28x%5Cright%29%7D%5C%5C%5C%5C%5Cmathrm%7BUse%5C%3Athe%5C%3Afollowing%5C%3Aidentity%7D%3A%5Cquad%20%5C%3A1%3D%5Ccos%20%5E2%5Cleft%28x%5Cright%29%2B%5Csin%20%5E2%5Cleft%28x%5Cright%29%5C%5C%5C%5C%3D%5Cfrac%7B%5Ccos%20%5E2%5Cleft%28x%5Cright%29%2B%5Csin%20%5E2%5Cleft%28x%5Cright%29%7D%7B%5Ccos%20%5Cleft%28x%5Cright%29%7D%5C%5C%5C%5C%5CRightarrow%20%5Cmathrm%7BTrue%7D)
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Answer:
Step-by-step explanation:
You have two methods to expand this binomial.
Method 1
If you have the expression:
You can write the expression it in the following way:
Then, apply the distributive property:
Simplify the expression:
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Method 2
For any expression of the form:
Its expanded form will be:
If
(2n2 + 4n + 4)(4n – 5)
= 8n^3 + 16n^2 +16n -10n^2 - 20n - 20
= 8n^3 +6n^2 -4n - 20
answer is d.
8n3 + 6n2 – 4n – 20