If the sum of the roots of 2 x squared - 6 x + 7 equals zero is multiplied by the product of its roots the result is

for 2x^2 - 6x + 7 = 0

the sum of the roots = -b/a = 6/2 = 3
product of the roots = c/a = 7/2

so (7/2)(3) = 21/3