Question

ПОМОГИТЕ!!!!срочно ,10 класс

Answer 1

1)15x²+8x+1=15(x+1/3)(x+1/5)
D=64-60=4
x1=(-8-2)/30=-1/3
x2=(-8+2)/30=-1/5)
20x²-31x+12=20(x-3/4)(x-4/5)
D=961-960=1
x1=(31-1)/40=3/4
x2=(31+1)/40=4/5
(15x²+8x+1)/(20x²-31x+12)≤0
             +            _            +                  _                +
-------------[-1/3]-------[-1/5]-----(3/4)----------(4/5)----------
x∈[-1/3;-1/5] U 93/4;4/5)
2){2x-x>8-2⇒x>6
   {x²-2x-63≥0⇒x≤-7 U x≥9
x1+x2=2 U x1*x2=-63⇒x1=-7 U x2=9
x∈[9;∞)