- 20 = - 20 which can be written as => 16-36 = 25-45 by adding (81/4) on both sides we get => 16-36+(81/4) = 25-45+(81/4) by writing the above eqn like this => ((4)2 -(2*4*(9/2)) +(9/2)2) = ((5)2 -(2*5*(9/2)) +(9/2)2) which is of the form => (a-b)2 = a2 + b2 -2ab here => a = 4 a = 5 b = 9/2 b = 9/2 from this we can write the above equation as => (4-(9/2)) 2 = (5-(9/2))2 by taking square root on both sides we get => +- (4-(9/2)) = +- (5-(9/2)) according to axioms when both sides are equal and having the same signs on both sides then both sides are positively equated to each other => 4 - (9/2) = 5 - (9/2) by shifting -(9/2) from left side to right side we get => 4 = 5 - (9/2) +(9/2) then as 9/2 gets cancelled we get => 4 = 5
