Question

The daily profit P ​(in thousands of​ dollars) from the sale of televisions is a function of the number x of televisions sold ​(in hundreds).
The formula for this function​ is:
P​ = -5x² + 13x - 4
What are the​ break-even sales amounts​ (the sales amounts that result in no profit or​ loss)?

Answer 1

Answer:

The break-even sales amounts​ is 36 or 224.

Step-by-step explanation:

Consider the provided function.

$P= -5x^2 + 13x - 4$

Where x is the number of televisions sold (in hundreds) and P is the profit.

We need to calculate the break-even sales amounts​.

the​ break-even sales amounts​ is the sales amounts that result in no profit or​ loss.

That means substitute P=0 and solve for x.

$-5x^2 + 13x - 4=0$

$5x^2-13x+4=0$

$\mathrm{For\:a\:quadratic\:equation\:of\:the\:form\:}ax^2+bx+c=0\mathrm{\:the\:solutions\:are\:}\\x_{1,\:2}=\frac{-b\pm \sqrt{b^2-4ac}}{2a}$

Substitute a=4, b=-13 and c=4 in above formula.

$x_{1,\:2}=\frac{-\left(-13\right)\pm \sqrt{\left(-13\right)^2-4\cdot \:5\cdot \:4}}{2\cdot \:5}$

$x_{1,\:2}=\frac{13\pm\sqrt{169-80}}{10}$

$x_{1,\:2}=\frac{13\pm\sqrt{89}}{10}$

$x=\frac{13+\sqrt{89}}{10},\:x=\frac{13-\sqrt{89}}{10}\\x\approx2.243, \ or\ x\approx 0.357$

Therefore, the break-even sales amounts​ is 36 or 224.