The graph of the function P(x) = −0.34x2 + 12x + 62 is shown. The function models the profits, P, in thousands of dollars for a tire company, where x is the number of tires produced, in thousands:

graph of a parabola opening down passing through points negative 4 and 57 hundredths comma zero, zero comma 62, 1 and 12 hundredths comma 75, 17 and 65 hundredths comma 167 and 55 hundredths, 34 and 18 hundredths comma 75, and 39 and 87 hundredths comma zero

If the company wants to keep its profits at or above $75,000, then which constraint is reasonable for the model?

−4.57 ≤ x ≤ 39.87
1.12 ≤ x ≤ 34.18
−4.57 ≤ x ≤ 1.12 and 34.18 ≤ x ≤ 39.87
0 ≤ x < 1.12 and 34.18 < x ≤ 39.87

1 answer

The constraint should be: 1.12 ≤ x ≤ 34.18. This is because this is the range of x-values for which the profits, P, are greater than or equal to $75,000. We can see from the graph that the profits start to dip below $75,000 outside of this range. The other options either include x-values where the profits are too low or exclude x-values where the profits are above $75,000.