Which shows one way to determine the factors of x3 + 5x2 – 6x – 30 by grouping?

x(x2 – 5) + 6(x2 – 5)
x(x2 + 5) – 6(x2 + 5)
x2(x – 5) + 6(x – 5)
x2(x + 5) – 6(x + 5)

The correct answer is: x(x2 – 5) + 6(x2 – 5)