I think it’s X=-3+(the square root of 2)
The answer is a= -4.181818
Answers are like this: 1)Cos C 2)Cos B 3)Cos A 4)a 5)b 6)c all of them are different type of writing cosines law , just this.
I am doing with Question Number 2
Let the two numbers be 'x' and 'y'.
According to the question, the product of two numbers is 14.

So, xy=14 (Equation 1)
Now, one of the numbers is 3 ½ times the other.
So, 
(Equation 2)
Substituting the value of 'x' from equation 2 in equation 1, we get



So, y= 2 and -2
So,
and 
x=7 and -7
Numbers are 2,7 and -2,-7.
Sum of numbers 2 and 7 = 9
Sum of numbers -2 and -7 = -9.
Answer:
b.
Step-by-step explanation:
We have to look at sign changes in f(x) to determine the possible positive real roots.

There is only one sign change here, between the -8x and the +4. So that means there is only 1 possible real positive root.
Now we have to look at sign changes in f(-x) to determine the possible negative real roots.

There are 3 sign changes here. That means there are either 3 negative roots or 3-2 = 1 negative root. So we have:
1 positive
3 or 1 negative
We need to pair them up now with all the possible combinations.
If we have 1 positive and 1 negative, we have to have 2 imaginary
If we have 1 positive and 3 negative, we have to have 0 imaginary
Keep in mind that the total number or roots--positive, negative, imaginary--have to add up to equal the degree of the polynomial. This is a 4th degree polynomial, so we will have 4 roots.