Answer:
z=16
Step-by-step explanation:
-7(z-6)= -70
combine -7 with the bracket
-7z + 42 = -70
-42 -42
-7z = - 112
divide both sides by -7
-7z/-7 = -112/-7
z = 16
check
-7(z-6)= -70
-7(16-6)= -70
combine
-112+42= -70
-42 -42
-112 = -112
For the line y=4x+5 the parent function is y=x
If you add two negative numbers you get a sum that is less than both of the numbers. so -1+-2=-3
You have the correct approximate value of k. The part after that is where things get a bit strange.
You don't plug in t = 5 again. We don't know the value of t yet. We're trying to solve for it.
We do know u(t) is 135 as we want the temperature to be 135 degrees. Plug this in and isolate t.
So
u(t) = 70+380e^(-0.1004183888t)
135 = 70+380e^(-0.1004183888t)
135-70 = 380e^(-0.1004183888t)
65 = 380e^(-0.1004183888t)
380e^(-0.1004183888t) = 65
e^(-0.1004183888t) = 65/380
e^(-0.1004183888t) = 13/76
-0.1004183888t = ln(13/76)
-0.1004183888t = -1.7657839828248
t = -1.7657839828248/(-0.1004183888)
t = 17.5842692152893
So it takes about 17.58 minutes for the item to cool to the desired temp
Answer: 346
Step-by-step explanation:
Given : Margin of error : E= 0.05
Standard deviation :
Significance level :
Critical value :
The formula to calculate sample size ( if proportion is known) :-
Hence, the required minimum sample would be 346.