(x-5)^2+(y+2)^2 = 81/4 What is its center and radius?

The brain volumes (cm cubed) of 50 brains vary from a low of 904 cm cubed to a high of 1488 cm cubed. use the range rule of thumb to estimate the standard deviation s and compare the result to the exact standard deviation of 175.5 cm cubed, assuming the estimate is accurate if it is within 15 cm cubed

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Solve each quadratic equation by factoring and using the zero product property. [tex]x^2+6x+8=0[/tex]