Question

Evaluate using suitable identities : 512

- 492​

Answer 1

$\huge\underline{\red{Answer}}$

${51}^{2} - {49}^{2} \\ = (51 + 49) \: (51 - 49) \\ = 100 \times 2 \\ = 200$

By using the formulae

${a}^{2} - {b}^{2} \\ = (a + b) \: (a - b$