Answer:
57 mph
Step-by-step explanation:
Let b represent Bob's speed on the trip. Then his time is ...
time = distance/speed
Bob's time = 230/b
Then John's speed is b+8, and his time is ...
John's time = 230/(b+8)
The difference of their times is 1/2 hour:
Bob's time - John's time = 1/2
230/b -230/(b+8) = 1/2 . . . substitute the expressions for time
460(b+8 -b) = b(b+8) . . . . . multiply by 2b(b+8)
b^2 +8b -3680 = 0 . . . . . . .put in standard form
(b +4)^2 -3696 = 0 . . . . . . . add 16-16 to complete the square
b = -4 +√3696 ≈ 56.795 . . . solve for positive b
Bob's drove about 57 mph on the trip.
Answer:
try one try one try one try one
There is no graph to tell
Sin 2x - sin 4x = 0
sin 2x - 2sin 2x cos 2x = 0
sin x(1 - 2cos 2x) = 0
sin x = 0 or 1 - 2cos 2x = 0
sin x = 0 or 2cos 2x = 1
sin x = 0 or cos 2x = 1/2
x = arc sin 0 or 2x = arc cos (1/2)
x = arc sin 0 or x = 1/2 arc cos (1/2)
x = 0, π, 2π or x = π/6, 7π/6
