Solve :

(x² + 5x + 4)(x² + 5x + 6) = 120

Solve: 5^x+1 + 5^2-x = 5³ + 1

If (k + 2)x² - 2x + 1 = 0 has real roots then greater value of k(∈ Z) is :

1. 1

2. 3

3. -1

4. none of these