Trinh has $3. He receives $20 in allowance from his parents. Then Trinh spends $20 on parts for his model rocket.
How much money does Trinh have left?
O A. $3
O B. $6
OC. $20
OD. $23

A. $3

Step-by-step explanation:

3+20=23

23-20=3

$3

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