Question

(a+1)²+(a-1)²-(a+1)(a-1)​

Answer 1

Step-by-step explanation:

$(a + 1) {}^{2} - (a + 1)(a - 1) + (a - 1) {}^{2}$

$(a + 1)(a + 1 -1) + (a - 1)(1 + a - 1)$

$a \times (a + 1) + a \times (a - 1)$

$a(a + 1 + a - 1)$

$2a \times a = 2a {}^{2}$

Answer is above

Answer 2

The answer is

${a}^{2} + 3$

Step-by-step explanation:

${(a + 1)}^{2} + {(a - 1)}^{2} - (a - 1)(a + 1)$

Opening brackets using (a+b)^2, (a-b)^2 and (a-b)(a+b)

${a}^{2} + 1 + 2a + {a}^{2} + 1 - 2a - ({a}^{2} - 1)$

${a}^{2} + 1 + 2a + {a}^{2} + 1 - 2a - {a}^{2} + 1$

Clearly, 2a will be cancelled out

$2 {a}^{2} - {a}^{2} + 3$

${a}^{2} + 3$