26. If both values AB and CD are perpendicular then if: A(1, 3), B(4, -2), C(6, 1), and D(x, y). Which are possible values of x and y?
A X = 1, y = -2
C X= 3, y= -4
B x= 3, y = 6
D x= -2, y = -4

(n^3 - n)

= n(n-1)(n+1)

since it is divisible by 3 and 2 ,because it is a multiple 3 consecutive number

if, n-1 is odd then n+1 is also odd, then it is a multiple of 9

but if, n-1 is even then n+1 is also even, then it is a multiple of 4

so, largest multiple = max(9*2, 4*3) = max(18, 12) = 18

no because after the troops were pulled many blacks were killed by hangings lynchings and other cruel ways which in a way interrupted the reconstruction of the south and differed from the way abraham lincoln had an idea of reconstruction