Start with
Subtract 240 from both sides:
Divide both sides by 12:
So, she needs to work at least 10 hours. Note that this is the minimum number of hours Ellie needs to work this week to earn at least $360 by the end of the month. This problem has no maximum: the more she works, the more she gains, so there's likely a typo in the question.
Given:
The image of a lens crosses the x-axis at –2 and 3.
The point (–1, 2) is also on the parabola.
To find:
The equation that can be used to model the image of the lens.
Solution:
If the graph of polynomial intersect the x-axis at c, then (x-c) is a factor of the polynomial.
It is given that the image of a lens crosses the x-axis at –2 and 3. It means (x+2) and (x-3) are factors of the function.
So, the equation of the parabola is:
...(i)
Where, k is a constant.
It is given that the point (–1, 2) is also on the parabola. It means the equation of the parabola must be satisfy by the point (-1,2).
Putting in (i), we get
Divide both sides by -4.
Putting in (i), we get
Therefore, the required equation of the parabola is .
Note: All options are incorrect.