Answer:
2.8a²+0.9a - 1.2
Step-by-step explanation:
Given the expression 0.3(3a-4)-0.05(8a)(-7a)
Expand using the distributive law
0.3(3a-4)-0.05(8a)(-7a)
0.3(3a)-0.3(4)-0.05(8a)(-7a)
0.9a-1.2 - 0.05(8a)(-7a)
0.9a - 1.2 + 2.8a²
Rearrange
2.8a²+0.9a - 1.2
Hence the required expression is 2.8a²+0.9a - 1.2
The explicit formula for given sequence is: 
Step-by-step explanation:
Given sequence is:
-1,4,-16,64.....
We can see that there is no same difference between consecutive terms so we will find common ratio to see if it is a geometric sequence.
Here

The explicit formula for geometric sequence is:

Putting the values of r and a1

Hence
The explicit formula for given sequence is: 
Keywords: Geometric sequence, common ratio
Learn more about geometric sequence at:
#learnwithBrainly
Answer:
after calculating I got this answer.
hope this answer helps you dear...take care
Answer:

Step-by-step explanation:

Answer:
It is an obtuse angle!
Step-by-step explanation: