Question

using identity find 72^2

Answer 1

72 x 68

72 x 68= (70 + 2) (70 – 2)

72 x 68= (70 + 2) (70 – 2)= (70)2 – (2)2 [Using in identity (a + b) (a – b) = a2 – b2]

72 x 68= (70 + 2) (70 – 2)= (70)2 – (2)2 [Using in identity (a + b) (a – b) = a2 – b2]= 4900 – 4

72 x 68= (70 + 2) (70 – 2)= (70)2 – (2)2 [Using in identity (a + b) (a – b) = a2 – b2]= 4900 – 4= 4896