(2√а + 3√b )^2 + (2√a + 3√b)*(2√a- 3√b)
(2√а + 3√b )^2 + (2√a + 3√b)*(2√a- 3√b)= 4a+12√ab+9b+4a-6√ab+6√ab-9b=8a+12√ab