For which system of inequalities is (3,-7) a solution?

a.
x + y < -4
3x + 2y < -5
b.
x + y ≤ -4
3x + 2y < -5
c.
x + y < -4
3x + 2y ≤ -5
d.
x + y ≤ -4
3x + 2y ≤ -5

answer:

step-by-step explanation:

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