1)1/(x+3)-1/(x+4)=1/(x+7)
x≠-3,x≠-4,x≠-7
(x+4)(x+7)-(x+3)(x+7)=(x+3)(x+4)
x²+11x+28-x²-10x-21-x²-7x-12=0
-x²-6x-5=0
x²+6x+5=0
x1+x2=-6 U x1*x2=5
x1=-5 U x2=-1-наиб
2)3x²+2x-1=(x+1)(3x-1)
D=4+12=16
(-2-4)/6=-1
x2=(-2+4)/6=1/3
2x²+x-1=(x+1)(2x-1)
D=1+8=9
x1=(-1-3)/4=-1
x2=(-1+3)/4=1/2
(3x²+2x-1)/(2x²+x-1)=(x+1)(3x-1)/(x+1)(2x-1)=(3x-1)/(2x-1)
3)(x-1)/x -3x/2(x-1)=-5/2
(x-1)/x=a
a-3/2a=-5/2
2a²+5a-3=0
D=25+24=49
a1=(-5-7)/4=-3⇔(x-1)/x=-3⇔x-1=-3x⇔4x=1⇔x=1/4
a2=(-5+7)/4=1/2⇔(x-1)/x=1/2⇔2x-2=x⇔x=2