Agraduated commission employee makes 3.5% interest on the first $50,000 in sales and 6.5% interest on all sales over $50,000. which of the following expressions represents the employee’s total earnings on $81,500 in sales?

you can't solve x because it is 2 linear equation and you only have one 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