For all real numbers x, find the minimum value of (x + 12)^2 - (x + 7)^2 + (x + 13)^2 - (x - 14)^2 + (x - 18)^2
Simplifying we get
x^2 - 28x + 392
The minimum value occurs at x = 28 / [ 2 * 1 ] = 14
And the minimum value is
(14)^2 -28(14) + 392 = 196
+1858 
