(\(\frac{2}{3}\)x2 + 5y2) (\(\frac{2}{3}\)x2 + 5y2) = (\(\frac{2}{3}\)x2 + 5y2)2
We have (a + b)2 = a2 + 2ab + b2
Here a = \(\frac{2}{3}\)x2
b = 5y2
(23 x2 + 5y2)2 = (23 x2)2 + 2 x 23 x2 (x) 5y2 + (5y2)2
= (\(\frac{2}{3}\))2 (x2)2 + \(\frac{20x^2y^2}{3}\) + 52(y2)2
(\(\frac{2}{3}\)x2 + 5y2)2 = \(\frac{4}{9}\)x4 + \(\frac{20x^2y^2}{3}\) + 25y4