Question

evaluate using identity 55×45

Answer 1

55 × 45

Here we can write 55 = 50 + 5 & 45 = 50 - 5

= ( 50 + 5 ) × ( 50 - 5 )

Using the identity III, ( a + b ) × ( a - b ) = a² - b²

= 50² - 5²

= 2,500 - 25

= 2,475

∴ 55 × 45 = 2,475

Answer 2

(50+5) (50-5) =( 50 )^2 - (5)^2 = 2500 - 25 = 2475