Shauntel is buying string and beads to make bracelets for her family and friends. She plans to divide the string into 7-inch pieces to make at least 20 bracelets. What is the minimum amount of string she needs to buy?

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step-by-step explanation:

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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