Bonjour,
Résoudre:
(5x²-12.5x-7.5)/(3-x)= 0 , x ≠ 3
5x²-12.5x-7.5= 0
Δ= (-12.5)²-4(5)(-7.5)= 306.25 > 0, existe 2 solutions
√306.25= 17.5
x1= (-(-12.5)- √306.25)/2(5)= (12.5-17.5)/10= -5/10= -1/2
x2= (12.5+17.5)/10= 30/10= 3
S= { -1/2 }
(x+20)/10= 10/x
x(x+20)= 10*10
x²+20x-100= 0
Δ= 20²-4(1)(-100)= 800 > 0, 2 solutions
√800= √(400x2)= 20√2
x1= (-20-20√2)/2= -10 -10√2
x2= (-20+20√2)/2= -10 +10√2
donc S= {x1; x2}
