Question

Calcule
X(x-1) = 11x -36

Answer 1

X²-X-11X+36=0
X²-12X+36=0


Δ=144-4·1·36
Δ=144-1444
Δ=0


X=12 (+-) √0
          2
x=12 (+-)0
         2
x=6

S={6;6}

Answer 2

x^2 -x = 11x - 36
x^2 -x -11x = -36
x^2 - 12x = -36
x^2 -12x -36 = 0
Δ= b² - 4 . a . c
Δ= 12² - 4.1.(-36)
Δ= 144 - 144
Δ= 0

X = - 6