bonjour
1 ) x² - 6 x + 3
α = 6 /2 = 3
β = 9 - 18 + 3 = - 6
x² - 6 x + 3 = ( x - 3)² - 6
2) 1 / ( x + 1) + 1 ( x + 2) = ( x + 2) / ( x + 1 ) ( x + 2) + ( x + 1) / ( x + 1 ) ( x +2)
= ( 2 x + 3 ) / ( x + 1) ( x + 2)
3) 1 - 1 / ( x - 1) = ( x - 1) / ( x - 1) - 1 / ( (x - 1 ) = ( x - 2) / ( x - 1)
f(x) = ( x - 4 )² + 2 x ( x + 5) - 17
f(x) = x² - 8 x + 16 + 2 x² + 10 x - 1 7
f (x) = 3 x² + 2 x - 1
f(x) = ( 3 x - 1 ) ( x + 1)
f (0) = - 1 * 1 = - 1
f (- 1) = - 4 * 0 = 0
f(x) = 0 donc x = 1/3 ou - 1
f(x) = - 1
3 x² + 2 x - 1 = - 1
3 x² + 2 x - 1 + 1 = 0
x ( 3 x + 2 ) = 0
x = 0 ou - 2/3
