bonjour
f (x) = 4 x² + 7 x - 3
α = - b / 2a
α = - 7 /8
β = 4 ( - 7/8 )² + 7 ( - 7/8 ) - 3 = 4 * 49/64 - 49/8 - 3
= 196/64 - 392/64 - 192/64 = - 388/ 64 = - 97/ 16
f (x) = 4 ( x + 7/8)² - 97/16
f (x) = 2 x² - 10 x + 3
α = 10 /4 = 5/2
β = 2 (5/2)² - 10*5/2 + 3
β = 2*25/4 - 50/2 + 3 = 50/4 - 100 /4 + 12/4 = - 38/4 = - 19/2
f (x ) = 2 ( x - 5/2)² - 19/2
