Answer:
Excuse me I need more information to solve this question.
Step-by-step explanation:
Answer:

Step-by-step explanation:
The sides AB and CD are parallel to the x-axis and 5 units apart. The length of side AB is 6-(-12) = 18 units. The area is the product of these dimensions:
Area = (Base)(Height) = (18 units)(5 units) = 90 units²
The circle equation is in the format (x – h)² + (y – k)² = r², with the center being at the point (h, k) and the radius being "r".
QUESTION 11.
Equation x²+y²+10x-14y-7 =0 can be rewritten as: x²+10x+25 + y² -14y + 49 -7 - 25 - 49=0
It can be factories as (x + 5)² + (y – 7)² = 9²
Therefore the radius equals 9 and the center is (-5,7)
QUESTION 12.
From equation (x + 4)² + y² = 121
The radius equals √121 = 11 and the center is (-4,0)
QUESTION 13.
As there are missing information in the question, I can't assist. However, you can use the general circle equation (x – h)² + (y – k)² = r² to solve the question.
Finally equations 14 & 15 aren't linear.
Hope that helps you :)
Answer: see proof below
<u>Step-by-step explanation:</u>
Given: A + B + C = π and cos A = cos B · cos C
scratchwork:
A + B + C = π
A = π - (B + C)
cos A = cos [π - (B + C)] Apply cos
= - cos (B + C) Simplify
= -(cos B · cos C - sin B · sin C) Sum Identity
= sin B · sin C - cos B · cos C Simplify
cos B · cos C = sin B · sin C - cos B · cos C Substitution
2cos B · cos C = sin B · sin C Addition
Division
2 = tan B · tan C

<u>Proof LHS → RHS</u>
Given: A + B + C = π
Subtraction: A = π - (B + C)
Apply tan: tan A = tan(π - (B + C))
Simplify: = - tan (B + C)

Substitution: = -(tan B + tan C)/(1 - 2)
Simplify: = -(tan B + tan C)/-1
= tan B + tan C
LHS = RHS: tan B + tan C = tan B + tan C 