Question

If a+b=25 and a^2+b^2=225 then find ab

Answer 1

(a+
$(a + b)2 = a2 + b2 + 2ab$
(25)2 = 225 + 2ab
625 = 225+ 2ab
625-225 = 2ab
400 = 2ab
ab = 400/2
therefore ab = 200