Answer:
A. T = 20°C - (2.8°C/h × 4h)
Step-by-step explanation:
The rate of change of temperature (-2.8°C/h) is multiplied by time (4h) to get the change in temperature (-11.2°C). That change is added to the initial temperature (20°C) to find the temperature after 4 hours.
Only equation A properly expresses this calculation.
In choice B, the rate of change is (wrongly) shown as +2.8°C/h. In the other choices, the combinations of units are nonsense. (What is a °C·h?)
Answer:
x=0, x= - 3, x=9
Step-by-step explanation:
f(x)=7/2x(x+3)(x-9)
f(x) doesn't exist for x=0,-3,9
as

vertical asymptote:
x=0, x= - 3, x=9
Answer:
What are you talking about? I didn't understand the question.
Answer:
HL
Step-by-step explanation:
Since we have two pairs of congruent sides with the included angle, one pair of which are the hypotenuses, then the triangles are congruent by HL.
Answer:
52 Hz
Step-by-step explanation:
We can divide the speed by the wavelength to find the number of waves propagated in one second:
(130 m/s)/(2.5 m/wave) = 52 waves/s
The SI unit of frequency is the Hertz, equal to one cycle per second.
The frequency of this wave is 52 Hz.
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<em>Additional comment</em>
The use of the unit Hz to signify frequency was adopted in 1933, but did not replace the unit "cycles per second" (CPS) until a number of years later.