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For the graph below, what should the domain be so that the function is at least 300?


graph of y equals minus 2 times the square of x plus 50 times x plus 300


x _ 0


-5 _ x _ 30


0 _ x _ 25


all real numbers

Verified Answer :

nobillionaireNobley

y = -2x^2 + 50x + 300
-2x^2 + 50x + 300 ≥ 300
-2x^2 + 50x ≥ 0
-2x^2 ≥ -50x
x^2 ≤ 25x
x ≤ 25

Therefore, required domain is 0 ≤ x ≤ 25

Answer:

The domain of the function so that the function is at least 300 is:

0 ≤ x ≤ 25

Step-by-step explanation:

We are given graph of the function y as:

\(y =-2x^2+50x+300\)

\(-2x^2+50x+300\geq 300\)

on subtracting both side of the inequality by 300 we obtain:

\(-2x^2+50x\geq 0\)

\(-2x(x-25)\geq 0\)

This inequality is obtained when one of the term is positive and the other is negative:

i.e. if x≥0

and x-25≤0

i.e. x≤25 then the product :

-2x(x-25)≥0.

Hence, the domain is:

  0 ≤ x ≤ 25

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