Cos² 2x = (1+cos 4x )/2
cos² 6x = (1+cos 12x)/2
subtract to get 1/2 (cos 4x - cos 12x )
= 1/2 (2 sin 4x sin 8x ) as cos A - cos B = 2 [ sin (A+B)/2 sin (A-B)/2 ]
so the answer
If x represents the mass of 1 ball in kg, then the balance shows ...
... 6x = x + 9 kg
... 5x = 9 kg
Then 6x is ...
... (6/5)·5x = (6/5)·9 kg = 10.8 kg
0.8 kg = 0.8·1000 g = 800 g
so 10.8 kg is ...
... D. 10 kg 800 g
<span>Let x = amt of water evaporated :.05(50) = .08(50-x) 2.5 = 4 - .08x .08x = 4 - 2.5 .08x = 1.5 x = 18.75 lb of water evaporated : ; Check; amt of salt remains the same, only the percentage is different, right? .05(50) = .08(50-18.75) .05(50) = .08(31.25) 2.5 = 2.5</span>
Answer:
the first option
Step-by-step explanation:
Start by substituting 15 for x. Then, simplify to get f(15)=36.
cuz
f(x)=2(x+3)
f(15)=2(15+3)
= 2×18=36
gimme brainliest plz
