作业帮a photo processing lab lists the following prices for reprints :29cents for a 3*5 print ; 39 cents for 4*6 print:and 55 cents for a 5*7 print find a quadratic function of the form f(x)=ax平方+bx+c that models the cost (in cents) per print in terms
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a photo processing lab lists the following prices for reprints :29cents for a 3*5 print ; 39 cents for 4*6 print:and 55 cents for a 5*7 print find a quadratic function of the form f(x)=ax平方+bx+c that models the cost (in cents) per print in terms
a photo processing lab lists the following prices for reprints :29cents for a 3*5 print ; 39 cents for 4*6 print:and 55 cents for a 5*7 print
find a quadratic function of the form f(x)=ax平方+bx+c that models the cost (in cents) per print in terms of the smaller dimension of the size
a photo processing lab lists the following prices for reprints :29cents for a 3*5 print ; 39 cents for 4*6 print:and 55 cents for a 5*7 print find a quadratic function of the form f(x)=ax平方+bx+c that models the cost (in cents) per print in terms
代入点（3,29）（4,39）（5,55）,解得a=3,b= -11,c= 35
Thus,the function is f(x)=3x^2-11x+35.
其实这题很简单,大概是因为你没有注意后面那个“smaller dimension”.这题我好像刷到过.
最后祝SAT加油!
quadratic function is f(x)=ax^2+bx+c
29 = a×15^2 + b×15 + c
39 = a×24^2 + b×24 + c
55 = a×35^2 + b×35 + c
这个实际上是三元一次线性方程。结果是：
a=0.0172, b=0.4414, c=18.515
f(x)=0.0172×x^2 + 0.4414×x + 18.515
quadratic function is f(x)=ax^2+bx+c
29 = a×15^2 + b×15 + c
39 = a×24^2 + b×24 + c
55 = a×35^2 + b×35 + c
这个实际上是三元一次线性方程。结果就是：
用a=0.0172, b=0.4414, c=18.515
f(x)=0.0172×x^2 + 0.4414×x + 18.515
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