Given a (A-1) - (a * a-b) = 8, find the value of a * a + b * B / 2-ab

Given a (A-1) - (a * a-b) = 8, find the value of a * a + b * B / 2-ab

a^2-a-a*a+b=8;
b-a=8;
b^2-2ab+a^2=64;
(a*a+b*b)/2-ab=(b^2-2ab+a^2)/2=32