X²-7x<6x-15-x² x²+x²-7x-6x+15<0 2x²-13x+15<0 D=(-13)²-4*2*15=169-120=49=7² x₁=(13+7)/(2*2)= 20/4=5 x₂=(13-7)/(2*2)=6/4=1,5 2x²-13x+15=2(x-5)(x-1,5) 2(x-5)(x-1,5)<0 (x-5)(x-1,5)<0 + - + _______________1,5_______________5_______________
x∈(1,5;5)