Can someone please help with these 2 questions? It would mean the world to me. I have attached the image for the questions.
2 answers:
Answer:
2
Step-by-step explanation:
for question a)
It would be easier if you converted these to improper fractions (currently it is in the form of a proper fraction)
to convert to improper fraction, you would multiply the denominator (bottom no. of fraction) by the whole number , then add that with the numerator (top no. of fraction) and put the whole thing over the denominator.
E.g.
7 = 7x4 + 1 = 29
Thus, improper fraction would be
do same thing for other one
thus ,
now,
-
however, you can't do this as the denominators are not the same, so multiply them by a number which would give the a common denominator (20 would be the best option for common denominator)
=
convert back to mixed number
2
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Answer:
Step-by-step explanation:
Use Newton's Law of Cooling for this one. It involves natural logs and being able to solve equations that require natural logs. The formula is as follows:
where
T(t) is the temp at time t
T₁ is the enviornmental temp
T₀ is the initial temp
k is the cooling constant which is different for everything, and
t is the time (here, it's in minutes)
If we are looking first for the temp after 20 minutes, we have to solve for the k value. That's what we will do first, given the info that we have:
T(t) = 80
T₁ = 30
T₀ = 100
t = 5
k = ?
Filling in to solve for k:
which simplifies to
Divide both sides by 70 to get
and take the natural log of both sides:
Since you're learning logs, I'm assuming that you know that a natural log and Euler's number, e, "undo" each other (just like taking the square root of something squared). That gives us:
Divide both sides by 5 to get that
k = -.0672944473
Now that we have a value for k, we can sub that in to solve for T(20):
which simplifies to
On your calculator, raise e to that power and multiply that number by 70:
T(20)= 30 + 70(.260308205) and
T(20) = 30 + 18.22157435 so
T(20) = 48.2°
Now we can use that k value to find out when (time) the temp of the object cools to 35°:
T(t) = 35
T₁ = 30
T₀ = 100
k = -.0672944473
t = ?
which simplifies to
Now divide both sides by 70 and take the natural log of both sides:
which simplifies to
-2.63905733 = -.0672944473t
Divide to get
t = 39.2 minutes
+ y = -1 ⇒ y =
- 1
To graph this line, plot a point at the y-intercept (0, -1), than plot the next point using the rise over run from the slope by counting up 1 and to the right 3 of the y-intercept. This gives you a second point of (3. 0). Draw a line through those two coordinates.
Answer: Plot (0, -1) and (3, 0) and draw a line through them.
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y = 4 + ⇒ y =
+ 4
Same as above. Plot the y-intercept (0, 4) and then use rise over run from the slope to plot (3, 5).
Answer: Plot (0, 4) and (3, 5) and draw a line through them.
***********************************************************************************
You should end up with two PARALLEL lines. Since the lines never intersect, there are no solutions to this system of equations.
Answer: No Solution