SOLUTION: The product of 3 consecutive positive integers is equal to 56 more than the cube of the first integer. What is the largest of these integers. a) 3 b)4 c)5 d)6 e)8

Algebra ->  Problems-with-consecutive-odd-even-integers -> SOLUTION: The product of 3 consecutive positive integers is equal to 56 more than the cube of the first integer. What is the largest of these integers. a) 3 b)4 c)5 d)6 e)8      Log On


   

Question 1040115: The product of 3 consecutive positive integers is equal to 56 more than the cube of the first integer. What is the largest of these integers.
a) 3
b)4
c)5
d)6
e)8
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
%28N-1%29N%28N%2B1%29=56%2B%28N-1%29%5E3
N%28N%5E2-1%29=56%2BN%5E3-3N%5E2%2B3N-1
N%5E3-N=N%5E3-3N%5E2%2B3N%2B55
3N%5E2-5N-55=0
%28N-5%29%283N%2B11%29=0
The positive solution is
N=5