-4.9t²+7.5t+1.8=2.1
-4.9t²+7.5t-0.3=0

t=-7.5±√(56.25-4*-4.9*-.3)/-2*4.9

t=-7.5±√(44.49/-9.8

t=(-7.5±6.67)/-9.8

t=-.83/-9.8 = .085 or t= -14.17/-9.8 = 1.446

8 0

2 years ago

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What is the solution set?<br><br> 12x−6.5>12 <br><br> Enter your answer in the box

Jlenok [28]

X > 1.54 this is the answer hope i helped

6 0

2 years ago

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Find the area of a square park whose perimeter is 400m

PIT_PIT [208]

Answer: 1600m^2

Its a square so all sides are equal. So...

400m * 400m

= 1600m^2

8 0

2 years ago

The life in hours of a thermocouple used in a furnace is known to be approximately normally distributed, with standard deviation

Effectus [21]

Answer:

62 is the minimum sample size needed

Step-by-step explanation:

We know that the population is approximately normally distributed so we will use a z-score for 95% confidence, which is 1.96. We are given the population standard deviation of σ = 20, and are given that the error should be 5 or less hours. The fact that it gives us sample data is irrelevant since we are told the population is approximately normally distributed and are given the population standard deviation.

See the attached photo for the calculation of the minimum sample size

8 0

2 years ago