Bonsoir,

-2x²+23x = 30

-2x²-23x-30 = 0

-2x²-23x+30 = 0

2x²-3x-20x+30 = 0

x*(2x-3)-10(2x-3) = 0

(2x-3)*(x-10) = 0

2x-3 =0               x-10 = 0

x= 3/2                 x =10

x₁ = 3/2 , x₂ = 10   ou   x₁ =1,5 , x₂ =10