Answer:
n = 23
Step-by-step explanation:
if 1/2 (n-5) = 1/2 (23-5)
that must mean that n=23.
and if you are just looking for 1/2 of 23-5 that is just 9. (23-5) = 18 and half of 18 is 9
Answer:
b. side angle side. hope this helps
12 *12 = 144
Therefore 12^2 = 144
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 
A - a removes both a’s from equation, then you’re left with b + bsquared, since they are unknown values you cannot combine them, even if it is the same letter, you can only add and subtract unknown values with their same letters together.