B). (-6,-7)
Hope this helps! Please make me the brainliest, it’s not necessary but appreciated, I put a lot of effort and research into my answers. Have a good day, stay safe and stay healthy.
Answer:

Step-by-step explanation:
The given number is 
We need to write this number in standard form.
Any no is given in the standard form is given by :

Where
a and b is real no and integer
It means,

Hence, this is the required solution.
-9-(-12)=-9+12=3
-9-12=-9+(-12)=-21
Answer:
B. 3
Step-by-step explanation:
Since you are given that chord AB's length is 8 and is bisected by segment XC, that means segment BC's length is 4 and ∠XCB is a right angle. From there, we use Pythagorean Theorem to solve for length XC:
4² + b² = 5² (Or remember 3-4-5 makes a Pythagorean triple)
c = √(5²-4²)
c = 3
6(-5n+7)=0
We simplify the equation to the form, which is simple to understand
6(-5n+7)=0
Reorder the terms in parentheses
+(-30n+42)=0
Remove unnecessary parentheses
-30n+42=0
We move all terms containing n to the left and all other terms to the right.
-30n=0-42
We simplify left and right side of the equation.
-30n=-42
We divide both sides of the equation by -30 to get n.
n=1.4
Hope this helps!