Lie is solving the quadratic equation by completing the square.

3x2 + 18x – 8 = 0

3x2 + 18x = 8

What should Lie do next?

Write the polynomial as a binomial squared.
Factor 3 out of the variable terms.
Isolate the variable x.
Add 8 to both sides of the equation.

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

a

step-by-step explanation:

you can use a^2+ b^2=c^2