Find the vertex of the graph of the equation y=-2x^2+18x-15.
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\(f(x) = ax² + bx + c\\ y=-2x^2+18x-15\)
\(x_v=-\frac{p}{2}=-\frac{\frac{18}{-2}}{2}\\ \color{blue}x_v=4.5\)
\(y_v=q-\frac{p^2}{4}=\frac{-15}{-2}-\frac{(\frac{18}{-2})^2}{4}\\ y_v=-2x_v^2+18x_v-15=-2\cdot 4.5^2+18\cdot 4.5-15\\ \color{blue}y_v=25.5\)
Informed at:
https://www.arndt-bruenner.de/mathe/10/scheitelpunkt.htm
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Continued in response to this post:
https://web2.0calc.com/questions/asap-i-am-upset-of-this
Ok I found my error, it was the middle square
Given | kept | total | |
jordan | \(\frac{2J}{3}\) | J/3 | J |
Kai | J/2 | J | 3J/2 |
Total | 7J/6 | 4J/3 | 300 |
\(J+\frac{3J}{2}=300\\ \frac{5J}{2}=300\\ J=120\\ check\\ (7*120/6)+(4*120/3)=300\;\;correct\)
So Kai keeps 120 marbles (which is the total number that Jordan has in the beginning)
given | kept | total | |
Jordan | 80 | 40 | 120 |
Kai | 60 | 120 | 180 |
Total | 140 | 160 | 300 |
Ok, I have checked your answer and it works so now I have to go back and find my error.
Refer back to the original question.
I've made a correction post.
This is the original post:
https://web2.0calc.com/questions/asap-please-math#r6
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Below is just what I did to check 120 was correct, then I went back to the original and posted a corrected solution.
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Say Kai did end up with 120 marbles.
He has 3/4 of the total number of marbles left
wich means that Kai ends up with 40
and there will be 160 marbles left at the end
there are 300 altogether so that means
so a total of 140 must have been given away
Jordan has half as many marbles left as what he gave away so that means he gave away 80.
That means that Jordan started out with 120 marbles
Also they gave away 140 marbles, 80 of them were Jordans so 60 must have been Kai's
Which means Kai started out with 180 marbles.
So far so good. Everything adds up perfectly
Now I need to check that it works with all the info
Kai and Jordan had 300 marbles altogether. tick
Kai gave away 25% fewer marbles than Jordan. tick
Jordan was left with 50% as many as the number of marbles he gave away. tick
Kai had 75% of the total number of marbles the boy left in the end. tick
How many marbles did Kai have in the end?
The answer is 120 marbles YES
Given | Kept | total | |
jordan | 80 | 40 | 120 |
Kai | 60 | 120 | 180 |
Total | 140 | 160 | 300 |
Cinderella was not actually an orphan in any of the early versions of the story.
Her father was alive and living with her. It made it more tragic for poor Aschenputtel (Cinderella from the Grimm's Brother' version) because her father let his new wife and stepdaughters abuse her.
The Grimm brothers' did not create fairy tales, they collected the ones, from the German countryside, that had been passed down orally through the generations. So their versions are very early versions. They were always very grim, unintended pun there, all the 'bad' people suffered horrible grissly punishments. Much too grissly for the protected ears of children today. Goodness always triumphed.
https://www.quora.com/What-happened-to-Cinderellas-parents-in-the-original-story