bonjour
x² - 8 x + 7 = 0
Δ = ( - 8 )² - 4 ( 1 * 7 ) = 64 - 28 = 36
x 1 = ( 8 - 6 ) / 2 = 2/2 = 1
x 2 = ( 8 + 6 ) / 2 = 14/2 = 7
2 x² + x - 3 = 0
Δ = 1 ² - 4 ( 2 * - 3 ) = 1 + 24 = 25
x 1 = ( - 1 - 5 ) / 4 = - 6 /4 = - 3 /2
x 2 = ( - 1 + 5 ) / 4 = - 4 /4 = - 1
