13. for which intervals is the function positive? a. (-infin, -3) and (-3, 1) b. (-1.5, 4.2) and (-infin, -3) c. (-2.5, 2.5) and (4,infin) d. (-3, 1) and (4,infin)

answer: 20

step-by-step explanation:

y=3n + 1

step-by-step explanation:

this is wrong because it says the second number is one less and i added one instead

answer: 204

step-by-step explanation:

we are told that the revenue is

x⋅(4080−10x)=−10x^2+4080x

this is a quadratic function, so to maximize it we should find the x-value of its vertex. recall that the x-value of the vertex of the parabola ax^2+bx+c is given by the formula −b/2a.

so in this case, we have a=−10 and b=4080, so the x-value of the vertex is

−b/2a= −(4080)/2(−10)=204

sorry i just need to anwers this to get points

step-by-step explanation: