(a + b)² - (a² + b²) = 2ab.

(a + b)² = a² + 2ab + b² by the expansion of the square of a binomial.

(x + 1)((x + 2) + (x - 2)) = (x + 1)(2x) = 2x² + 2x.

(x + 1)(x - 1) = x² - 1, which is the difference of squares.

(x + 2)(x - 2) = x² - 4 by the difference of squares identity.

(x + 2)² = x² + 4x + 4; thus, (x + 2)² - (x² + 4) = 4x.

(x + 3)(x - 3) = x² - 9 by the difference of squares formula.

(x + y + z)² = x² + y² + z² + 2xy + 2yz + 2zx by the expansion of the square of a trinomial.

(x + y)(x - y) = x² - y² by the difference of squares identity.

(x - 4)(x + 4) = x² - 16.

Multiplying three negative ones gives −1.

(−1)^3 = −1.

(−1)² = 1 and (−2)² = 4, so 1 + 4 = 5.

(−1)³ = −1.

(−2)² = 4.

(−5)² = 25.

−7 + (−3) = −10.

(√(49) + √(16)) = 7 + 4 = 11, so 11 / 5 = 2.2, which rounds to 2.

Calculating gives 12 + 15 = 27, and then 27 - 7 = 20.

Following the order of operations, first calculate 3 × 2 = 6. Then, 12 - 6 + 4 = 10.

15% of 600 = (15/100) * 600 = 90.

2^3 = 2 * 2 * 2 = 8.

2^5 = 2 × 2 × 2 × 2 × 2 = 32.

Calculating 2^5 = 32 and 3^3 = 27. Therefore, 32 + 27 = 59.

According to BODMAS, 4 × 2 = 8, so 3 + 8 = 11.

3.5 + 2.8 = 6.3.

3² = 9 and 4² = 16. So, 9 + 16 = 25.

3√(27) = 3 × 3 = 9.

7! = 7 * 6 * 5 * 4 * 3 * 2 * 1 = 5040.

7! = 7 × 6 × 5 × 4 × 3 × 2 × 1 = 5040