SOLUTION: Each of the three dimensions of a cube with a volume of y^3 cubic centimeters is decreased by a whole number of centimeters. If the new volume is y^3 - 13y^2 +54y - 72 cubic centim

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: Each of the three dimensions of a cube with a volume of y^3 cubic centimeters is decreased by a whole number of centimeters. If the new volume is y^3 - 13y^2 +54y - 72 cubic centim      Log On


   



Question 76558: Each of the three dimensions of a cube with a volume of y^3 cubic centimeters is decreased by a whole number of centimeters. If the new volume is y^3 - 13y^2 +54y - 72 cubic centimeters and the new width is y-6 centimeters, then what are the new length and height?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
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Each of the three dimensions of a cube with a volume of y^3 cubic centimeters is decreased by a whole number of centimeters. If the new volume is y^3 - 13y^2 +54y - 72 cubic centimeters and the new width is y-6 centimeters, then what are the new length and height?
:
Find the product of the new length and height by dividing y^2 - 13y^2 + 54y - 72
by (y-6)
use synthetic division:
:....___________________________
+6 | 1 - 13 + 54 - 72
............+ 6 - 42 + 72
......------------------
........1 - 7 + 12 + 0
:
That gives us: y^2 - 7y + 12
This factors to: (y-3)(y-4)
:
The new length = (y-3)
The new height = (y-4)
or vice-vera