By driving 8 mph faster than bob, john can make a 230 mile trip in one half hour less. how fast does bob drive on the trip? round your answer to the nearest mile per hour

  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.

  n=   0.0000 - 0.3750 i  

  n=   0.0000 + 0.3750 i

step-by-step explanation:

one of these should be correct

step-by-step explanation:

first, eliminate the parenthesis:

3

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+

2

−

4

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second, group like terms:

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4

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third, combine like terms:

(

3

−

4

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x

+

2

→

−

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→

−

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