Answer:
look it up
Step-by-step explanation:
The percentage of Change in time is an decrease
In this big ol' word problem, this is just an instance of basic multiplication/division.
If it takes it 1 hour for 3 meters...
12 ÷ 3 = 4.
It would take 4 hours for the water level to change to 12 meters.
I got 270. hope this helped
![f(x)=\quad 2{ x }^{ 2 }+3x+5](https://tex.z-dn.net/?f=f%28x%29%3D%5Cquad%202%7B%20x%20%7D%5E%7B%202%20%7D%2B3x%2B5)
Let's called the input 'z'
When we plug 'z' in the function we get ;
![f(z)=\quad 2{ z }^{ 2 }+3z+5](https://tex.z-dn.net/?f=f%28z%29%3D%5Cquad%202%7B%20z%20%7D%5E%7B%202%20%7D%2B3z%2B5)
And we know that, this is equal to 19, so ;
![2{ z }^{ 2 }+3z+5=\quad 19](https://tex.z-dn.net/?f=2%7B%20z%20%7D%5E%7B%202%20%7D%2B3z%2B5%3D%5Cquad%2019)
Let's rearrange the equation.
![2{ z }^{ 2 }+3z+5=\quad 19\\ \\ 2{ z }^{ 2 }+3z=\quad 19-5\\ \\ 2{ z }^{ 2 }+3z=\quad 14\\ \\ 2{ z }^{ 2 }+3z-14=\quad 0](https://tex.z-dn.net/?f=2%7B%20z%20%7D%5E%7B%202%20%7D%2B3z%2B5%3D%5Cquad%2019%5C%5C%20%5C%5C%202%7B%20z%20%7D%5E%7B%202%20%7D%2B3z%3D%5Cquad%2019-5%5C%5C%20%5C%5C%202%7B%20z%20%7D%5E%7B%202%20%7D%2B3z%3D%5Cquad%2014%5C%5C%20%5C%5C%202%7B%20z%20%7D%5E%7B%202%20%7D%2B3z-14%3D%5Cquad%200)
So we have a quadratic equation here.
We'll use this formula to solve it :
![\frac { -b\pm \sqrt { { b }^{ 2 }-4ac } }{ 2a }](https://tex.z-dn.net/?f=%5Cfrac%20%7B%20-b%5Cpm%20%5Csqrt%20%7B%20%7B%20b%20%7D%5E%7B%202%20%7D-4ac%20%7D%20%20%7D%7B%202a%20%7D%20)
The formula is used in equation formed like this :
![a{ x }^{ 2 }+bx+c=0](https://tex.z-dn.net/?f=a%7B%20x%20%7D%5E%7B%202%20%7D%2Bbx%2Bc%3D0)
In our equation,
a=2 , b=3 and c=-14
Let's plug in the values in the formula to solve,
![a=2\quad b=3\quad c=-14\\ \\ \frac { -3\pm \sqrt { 9-(4\cdot 2\cdot -14) } }{ 4 } \\ \\ \frac { -3\pm \sqrt { 9-(-112) } }{ 4 } \\ \\ \frac { -3\pm \sqrt { 9+112 } }{ 4 } \\ \\ \frac { -3\pm \sqrt { 121 } }{ 4 } \\ \\ \frac { -3\pm 11 }{ 4 }](https://tex.z-dn.net/?f=a%3D2%5Cquad%20b%3D3%5Cquad%20c%3D-14%5C%5C%20%5C%5C%20%5Cfrac%20%7B%20-3%5Cpm%20%5Csqrt%20%7B%209-%284%5Ccdot%202%5Ccdot%20-14%29%20%7D%20%20%7D%7B%204%20%7D%20%5C%5C%20%5C%5C%20%5Cfrac%20%7B%20-3%5Cpm%20%5Csqrt%20%7B%209-%28-112%29%20%7D%20%20%7D%7B%204%20%7D%20%5C%5C%20%5C%5C%20%5Cfrac%20%7B%20-3%5Cpm%20%5Csqrt%20%7B%209%2B112%20%7D%20%20%7D%7B%204%20%7D%20%5C%5C%20%5C%5C%20%5Cfrac%20%7B%20-3%5Cpm%20%5Csqrt%20%7B%20121%20%7D%20%20%7D%7B%204%20%7D%20%5C%5C%20%5C%5C%20%5Cfrac%20%7B%20-3%5Cpm%2011%20%7D%7B%204%20%7D%20)
So,
![z=\quad \frac { -3+11 }{ 4 } \quad ,\quad \frac { -3-11 }{ 4 } \\ \\ z=\quad \frac { 8 }{ 4 } \quad ,\quad \frac { -14 }{ 4 } \\ \\ z=\quad 2,\quad -\frac { 7 }{ 2 }](https://tex.z-dn.net/?f=z%3D%5Cquad%20%5Cfrac%20%7B%20-3%2B11%20%7D%7B%204%20%7D%20%5Cquad%20%2C%5Cquad%20%5Cfrac%20%7B%20-3-11%20%7D%7B%204%20%7D%20%5C%5C%20%5C%5C%20z%3D%5Cquad%20%5Cfrac%20%7B%208%20%7D%7B%204%20%7D%20%5Cquad%20%2C%5Cquad%20%5Cfrac%20%7B%20-14%20%7D%7B%204%20%7D%20%5C%5C%20%5C%5C%20z%3D%5Cquad%202%2C%5Cquad%20-%5Cfrac%20%7B%207%20%7D%7B%202%20%7D%20)
So the input can be both, 2 and