Answer:
Step-by-step explanation:
Hello there! An example problem for this could be:
Emile is looking for a cell-phone plan. His two options are one that costs $40 up front, and costs $0.01 per text, represented by x. The second one is 15 dollars up front and costs $0.06 for each text message. Emile figures that for the first package he has to send 500 texts or more to make it less than the second one.
Answer:
47.5 and 2853.56 m
Step-by-step explanation:
Graph the equation on desmos and use the graph to find the maxima and the roots
Set the whole expression = to 0 and solve for x.
3x^(5/3) - 4x^(7/3) = 0. Factor out x^(5/3): x^(5/3) [3 - 4x^(2/3)] = 0
Then either x^(5/3) = 0, or 3 - 4x^(2/3) = 0.
In the latter case, 4x^(2/3) = 3.
To solve this: mult. both sides by x^(-2/3). Then we have
4x^(2/3)x^(-2/3) = 3x^(-2/3), or 4 = 3x^(-2/3). It'd be easier to work with this if we rewrote it as
4 3
--- = --------------------
1 x^(+2/3)
Then
4
--- = x^(-2/3). Then, x^(2/3) = (3/4), and x = (3/4)^(3/2). According to my 3 calculator, that comes out to x = 0.65 (approx.)
Check this result! subst. 0.65 for x in the given equation. Is the equation then true?
My method here was a bit roundabout, and longer than it should have been. Can you think of a more elegant (and shorter) solution?
Well the first thing you have to do is find out how many times 7 goes into 50 whole. This is 7. So then you take the answer to (7x7) from 50 which gives you one, and put it over 50. This equals 7 + 1/50