- #1
Evangeline101
- 112
- 5
Homework Statement
Homework Equations
none
The Attempt at a Solution
Is this correct?
Thanks.
The answer is correct.Evangeline101 said:Homework Statement
[ ATTACH=full]101053[/ATTACH]
Homework Equations
none
The Attempt at a Solution
[ ATTACH=full]101054[/ATTACH]
Is this correct?
Thanks.
Evangeline101 said:Homework Statement
View attachment 101053
Homework Equations
none
The Attempt at a Solution
View attachment 101054
Is this correct?
Thanks.
SammyS said:The answer is correct.
There are errors in your work starting with the table.
If x is the speed from Tokyo to Bangkok then reducing that by 200 gives a speed of x - 200 from Bangkok to Tokyo. Etc.
There's still a problem, x is the Tokyo to Bangkok speed. That can't be 600mph. 600 - 200 is 400, and that doesn't work out.Evangeline101 said:I understand where I made the error, the return trip speed decreased by 200 km/h, so it should have been (x-200) not (x+200), so I have corrected my answer:[ ATTACH=full]101104[/ATTACH]
Thanks for the help! :)
I tried doing it this way, but as you said there is no real solution.SammyS said:There's still a problem, x is the Tokyo to Bangkok speed. That can't be 600mph. 600 - 200 is 400, and that doesn't work out.
So, where is the problem?
You made a couple of errors.
Sign errors in going from
−960000=2x2−400x−960000=2x2−400x-960000=2x^2-400x to
2x2+400x−960000=02x2+400x−960000=02x^2+400x-960000= 0 It should be
2x2−400x+960000=02x2−400x+960000=02x^2-400x+960000= 0 But there is no real solution to that.
SammyS said:The problem is that it's the Tokyo to Bangkok time that's smaller, because the speed is greater. When you subtract to get 2 hours, you need to subtract in the opposite order.
If x > 200, thenEvangeline101 said:I tried doing it this way, but as you said there is no real solution.
I don't understand what you mean, can you please explain?
SammyS said:If x > 200, then
4800x−200>4800x4800x−200>4800x\displaystyle \frac{4800}{x-200}>\frac{4800}{x}.
So you had these reversed.
It's what is needed of you want to make everything consistent.Evangeline101 said:So even if I switch these two, can I not get the same answer I had originally? How does switching the two help with the answer to the problem? or is it just the proper way to write it?
SammyS said:It's what is needed of you want to make everything consistent.
As I stated in my first reply, the answer you gave for the time from Bangkok to Tokyo was correct. (600 km/hr)
But you had a number of inconsistencies.
Added in Edit:
You should get x = 800. Then x- 200 = 600, the answer.
No.Not like that.Evangeline101 said:
SammyS said:You should get x = 800. Then x- 200 = 600, the answer.
Right. And they did not make algebra mistakes. You did.Evangeline101 said:This is an example from my lesson that I have been using as a reference to solve my problem:
View attachment 101173
View attachment 101174
SammyS said:No.Not like that.
The first three lines are correct.
After that, there are at least two Algebra mistakes.
Yes. That looks to be correct.Evangeline101 said:View attachment 1011774800x - 4800x + 960 000 = 2x2 - 400x (960 000 is positive because I multiplied -4800 and -200)
960 000 = 2x2 - 400x (Now I move 960 000 to the right side and it becomes -960 000)
2x2 - 400x - 960 000 = 0
x2 - 200x - 480 000 = 0
(x+600) (x-800) = 0
x= -600 or x = 800
Does this make more sense? did I fix the algebra errors? if not please show me where I made errors.
SammyS said:You should get x = 800. Then x- 200 = 600, the answer.
A quadratic function is a type of mathematical function that can be written in the form f(x) = ax^2 + bx + c, where a, b, and c are constants and x is the independent variable. It is a polynomial function of degree 2, meaning the highest power of x is 2.
To find the equation of a quadratic function, you need to know three key points on the graph of the function. These points can be in the form of coordinates (x, y). Once you have these points, you can use the point-slope form or the standard form of a quadratic equation to find the equation. Alternatively, if you know the vertex and one other point, you can use the vertex form to find the equation.
The vertex of a quadratic function is the highest or lowest point on the graph of the function. It is also the point where the function changes direction from increasing to decreasing or vice versa. The x-coordinate of the vertex can be found by using the formula x = -b/2a, and the y-coordinate can be found by substituting the x-coordinate into the function.
Yes, a quadratic function can have zero, one, or two x-intercepts. The number of x-intercepts depends on the discriminant of the quadratic equation, which is b^2 - 4ac. If the discriminant is greater than zero, the function will have two x-intercepts. If it is equal to zero, the function will have one x-intercept. And if it is less than zero, the function will have no x-intercepts.
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