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 
Answer:
6/12
Step-by-step explanation:
the last one
4/8=6/12!!
Answer:
The answer is 1-5x+135y
Step-by-step explanation: multiply the numbers 3 and 45 which give you 135
Answer:
Step-by-step explanation:
Speed = distance travelled/time
A horse ran 800 m in 40 seconds. This means that the speed is
800/40 = 20 m/s
The horse ran 1200 m in 60 seconds. This means that the speed is
1200/60 = 20 m/s
The horse ran 1200 m in 60 seconds. This means that the speed is
480/24 = 20 m/s
Since the horse's rate or speed is the same at each scenario, it means that the relationship between the distance covered by the horse and the time taken is proportional.
Let k represent the constant of proportionality. The constant of proportionality is 20. It represents speed of the horse.
Let d represent the distance in meters.
Let t represent the time in seconds.
Therefore
d = 20t
Answer:
22 + 27 = <u><em>49</em></u>
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:) :)