WRITE IT AS
Recall that a composite number is a nonprime positive integer. We will call a composite number n a simple composite if it is the product of distinct primes and a complex composite if it has a factor of the form p2 for some prime p.
Write 12,167 in the form a1 + a2 + ××× + a9 + b where each ai is a complex composite and b is a simple composite.
Weng Shao
Observe that (x + y + z)3 = x3 + 3x2y + 3x2z + 3xy2 + 6xyz + 3xz2 + y3 + 3y2z + 3yz2 + z3.
So
12,617 = (23)3 = (5 + 7+11)3 = 53 + 3×52×7 + 3×52 ×11 + 3 ×5 ×72 + 3 ×5 ×112 + 73 + 3× 72 ×11 + 3 ×7×112 + 113 + 3×2× 5× 7× 11
Nathan Collins
a1 = a2 = ··· = a9 = 22 and b = 7 · 1733
36 + 12131 = 12167
Josiah Thornton
233 = (21 + 2)3 = 213 + 3× 212 ×2 + 3 × 21× 22 + 23 =
21 3 + 2906 = (19 + 2)3 + 2906 =
193 + (3× 192 ×2 + 3 ×19× 22 + 23 ) + 2906 = 173 + 3× 172 ×2 + 3 ×17× 22 + 23 + (3× 192 ×2 + 3 ×19× 22 + 23 )
+ 2906 = 12167
a1 = 173, a2 = a3 = 3 ×19× 2, a4 = a5 = 3× 172, a6 = 3 ×19× 22 , a7 = 3 ×17× 22, a8 = a9 = 23
b = 2906 = 2× 1453
|