If ur looking for the mean it would be 4.7
Let is the answer for the question
Answer:
First row. = -393 74 287
Second row = 471. 162 91
Third row =251 222 - 349
Step-by-step explanation:
For the first row
Cofactor of 12= (-8*15)-(21*13)
= -120-273
= -393
Cofactor of 23 = (11*15)-(7*13)
= 165-91
= 74
Cofactor of -6 = (11*21)-(-7*8)
= 231+56
= 287
For the second row
Cofactor of 11 = (23*15)-(21*-6)
= 345+126
= 471
Cofactor of -8 = (12*15)-(7*-6)
= 120 + 42
= 162
Cofactor of 13 (12*21)-(23*7)
= 252-161
= 91
For third row
Cofactor of 7= (23*13)-(-8*-6)
= 299-48
= 251
Cofactor of 21 = (12*13)-(11*-6)
= 156+66
=222
Cofactor of 15 = (12*-8)-(11*23)
= -96 - 253
=- 349
From the double-angle identity,

we can rewritte our given equation as:

By factoring 2cosx on the left hand side, we have

This equation has 2 solutions when

From equation (A), we obtain

and from equation (B), we have

On the other hand, we can find one more solution from the original equation by substituting x=0, that is,

then, x=0 is another solution. In summary, we have obtained the following solutions:

However, the intersection of the last set is empty. So the unique solution is x=0 as we can corroborate on the following picture:
Therefore, the solution set is: {0}
1) 6.6 * 3.3 = 21.78
2) (10^ - 2 )*(10^ - 4) = 10 ^ ( -2 - 4) = 10 ^ - 6
3) result: 21.78 * 10 ^ - 6
4) to convert to standard form run the period on space to the lef and multiply the ten base by 10 =>
2.178 * 10 ^ - 5
Answer: 2.178 * 10 ^ - 5