13(x²-3x)/2-12/(x²-3x)=3x≠0 U x≠3x²-3x=a3a/2-12/a=33a²-6a-24=0a²-2a-8=0a1+a2=2 U a1*a2=-8a1=-2⇒x²-3x=-2x²-3x+2=0x1=x2=3 U x1*x3=2x1=1 U x2=2a2=4⇒x²-3x=4x²-3x-4=0x3=x4=3 U x3+x4=-4x3=-1 U x4=4Ответ x={-1;1;2;4}26/(x²+3x+2)+8/(x²+3x-4)=1x≠-4;x≠-1;x≠-2;x=1x²+3x=a6/(a+2)+8/(a-4)=16a-24+8a+16-a²+2a+8=0a²-16a=0a(a-16)=0a=0⇒x²+3x=0x(x+3)=0x1=0 U x2=-3a-16=0⇒a=16⇒x²+3x=16x²+3x-16=0D=9+64=73x3=(-3-√73)/2 x4=(-3+√73)/2Ответ x={(-3-√73)/2;-3;0;(-3+√73)/2}3(x²+8x)(x²+8x+15)=100x²+8x=aa(a+15)=100a²+15a-100=0a1+a2=-15 U a1*a2=-100a1=-20⇒x²+8x=-20x²+8x+20=0D=64-80=-16<0 нет решенияa2=5⇒x²+8x=5x²+8x-5=0D=64+20=84x1=(-8-2√21)/2=-4-√21x2=-4+√21Ответ x={-4-√21;-4+√21}