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Answer:</h2><h2>The expressions that can be subtracted from 9x to result in the expression 3x+5 is 6x - 5</h2>
Step-by-step explanation:
To find the expression that can be subtracted from 9x to result in the expression 3x+5.
Let us consider the expression, a - b = c
Here a = 9x
the result, c = 3x + 5
b = ?
Substitute the values in the above equation, we get
9x - b = 3x + 5
9x - (3x + 5) = b
b = 6x - 5
Move constant over (5x=38+2), combine terms (5x=40), divide both sides by 5 (x=8)
First set up your two equations:
x + y = 90
x = 2y - 30
Then substitute what x equals in the second equation into the first equation:
(2y -30) + y = 90
Now solve for y:
3y -30 = 90
3y = 120
y = 40
Then use y = 40 and substitute the value for y into one of your original equations and solve for x. I'll choose the first one, but either one will work.
x+ 40 = 90
x = 50
So your solution is x = 50 and y = 40
Answer:
The refrigerator was at around 13 ∘C
Step-by-step explanation:
Newton's Law of Cooling:
The rate of change of a body temperature (amount of heat loss/time of loss) is directly proportional to the difference between its own temperature and the surroundings.
T ⇒ temperature
t ⇒ time
Tenv ⇒refrigerator temperature
⇒ rate of change of he temperature
-h ⇒ constant of proportionality (negative because the temperature is decreasing inside the refrigerator)
We have 3 points:
time (minutes) - Temperature (∘ C)
0 (when the pan was put in the refrigerator) - 46
15 (after 15 minutes) - 27
30 (15 minutes after the first 15 minutes) - 19
= -h (27 - Tenv)
= -h (19 - Tenv)
Now we have a system of two equations and two variables
The refrigerator was at around 13 ∘C
\left[A \right] = \left[ \frac{ - \left( 5 - 3\,x - 2\,x^{2} - 2\,x^{3}\right) }{-1-x}\right][A]=[−1−x−(5−3x−2x2−2x3)] I hope helping this answer
