Question

Square of (3.49)-square of (2.51))/3.49-2.51

Answer 1

[(3.49²) - (2.51²)]/(3.49 - 2.51)   [∵ (a²-b²) = (a+b)(a-b)  ]
⇒[(3.49 + 2.51)(3.49 - 2.51)]/(3.49 - 2.51)
⇒(3.49 + 2.51) = 6