\(M=\left(x-1\right)\left(x+2\right)\left(x+3\right)\left(x+6\right)\)

\(=\left[\left(x-1\right)\left(x+6\right)\right]\left[\left(x+2\right)\left(x+3\right)\right]\)

\(=\left(x^2+5x-6\right)\left(x^2+5x+6\right)\)

\(=\left(x^2+5x\right)^2-36\ge-36\)

=> The minimum of M is -36 when x = 0 or x = -5

M=(x−1)(x+2)(x+3)(x+6)

=[(x−1)(x+6)][(x+2)(x+3)]

=(x2+5x−6)(x2+5x+6)

=(x2+5x)2−36≥−36

=> The minimum of M is -36 when x = 0 or x = -5

We have :

M = (x - 1) (x + 2) (x + 3) (x + 6)

=[(x - 1) (x + 6)] [(x + 2) (x + 3)

= (x . x + 5x - 6) (x . x + 5x + 6)

= (x.x + 5x)² - 36

= (x² + 5x)² > or = -36

The answer is : 

M is 36 when x = 0

                       x = -5

false The answer is 

M is -36 when x = 0

                        x = -5