15 - n when n equals 9 = 6
n3 + 3n2 + 4n + 12 = (n3 + 3n2) + (4n + 12) = n2(n + 3) + 4(n + 3) = (n2 + 4)(n + 3).
Add 7 to each side: 3n2 = 7 Divide each side by 3: n2 = 7/3 n = sqrt 7/sqrt 3, ie just over 1.5
n = 8
x = 15 - N.
-((3n - 1)(n + 3))
n + 15 = 36 Therefore, n = 36 - 15 n = 21
3n2 - 7n = 0 n(3n - 7) = 0 So either n = 0 or 3n-7 = 0 ie, either n = 0 or n = 7/3 = 21/3 = 2.33...
450/15 = 30
n+15 = 52 n = 52-15 n = 37
t(n) = 3n2 + n = n(3n + 1)
(3n+2)(n+1)