#22 algebra?
回答 (2)
2015-08-29 8:40 pm
try these yourself....V = 6 [ x ] [ x + 12] = 1728....find x
2015-08-29 8:45 pm
Height = 6
Length = (x+12) - 2·6 = x
Width = x - 2·6 = x-12
volume = HLW = 6x(x-12)
6x(x-12) = 1728
x(x-12) = 288
x² - 12x - 288 = 0
Quadratic formula
x = [12 ± √(12² – 4·1(-288))] / [2·1]
= [12 ± √1296] / 2
= [12 ± 36] /2
= -12, 24
-12 is an extraneous solution
x = 24 inches
The sheet of cardboard is 24 inches wide and 30 inches long.
Length = (x+12) - 2·6 = x
Width = x - 2·6 = x-12
volume = HLW = 6x(x-12)
6x(x-12) = 1728
x(x-12) = 288
x² - 12x - 288 = 0
Quadratic formula
x = [12 ± √(12² – 4·1(-288))] / [2·1]
= [12 ± √1296] / 2
= [12 ± 36] /2
= -12, 24
-12 is an extraneous solution
x = 24 inches
The sheet of cardboard is 24 inches wide and 30 inches long.
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