1) 36x^2 - 36x + 9 = (6x - 3)^2
x = 0.5
(6*0.5-3)^2 = 0
2) 49a^2 - 56ab +16b^2 = (7a - 4b)^2
a = 0.6, b = 0.4
(4.2 - 1.6)^2 = 2.6^2 = 6.76
