
Mark M. answered 04/16/19
Mathematics Teacher - NCLB Highly Qualified
Two consecutive even integers:
n and n + 2
n(n + 2) = n + 30
Can you solve for n and answer?
Mark M. answered 04/16/19
Mathematics Teacher - NCLB Highly Qualified
Two consecutive even integers:
n and n + 2
n(n + 2) = n + 30
Can you solve for n and answer?
Let N be the first integer. Then N+2 is the next even integer. Expressing what we know:
N * (N+2) = N + 30
N^2 + 2N = N + 30
N^2 + N = 30
therefore
N * (N+1) = 30
therefore N = -6 since -6 * (-5) = 30.
the second integer is
N + 2 = -4.
Working it by the quadratic formula:
N^2 + N - 30 = 0
N = {-1 +/- sqrt(1 + 4 * 1 * 30} / 2
N = (-1/2) +/- sqrt(121)/2 = (-1/2) +/- 11/2
therefore N = 5 or -6
N = 5 is not even so
N = -6 as before.
Checking
(-6)*(-4) = 30 + (-6) - check!
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