1
2/(x-3)=7/(x+1)
ОЗ (x-3)(x+1)≠0⇒x≠3;x≠-1
2(x+1)=7(x-3)
2x+2=7x-21
7x-2x=2+21
5x=23
x=23:5
x=4,6
2
x/(2x+6)=2/x
ОЗ x(2x+6)≠0⇒x≠0;x≠-3
x*x=2*(2x+6)
x²-4x-12=0
D=16+48=64
x1=(4-8)/2=-2
x2=(4+8)/2=6
3
3/x+3/(x+2)=4
ОЗ x(x+2)≠0⇒x≠0,x≠-2
3*(x+2)+3*x=4*x(x+2)
4x²+8x-3x-6-3x=0
4x²+2x-6=0
D=4+96=100
x1=(-2-10)/8=-1,5
x2=(-2+10)/8=1
4
1/(x+2)+1/x(x-2)=8/x(x-4)
Оз x(x+2)(x-2)(x-4)≠0⇒x≠0,x≠-2,x≠2,x≠4
x(x-2)(x-4)+(x+2)(x-4)=8(x+2)(x-2)
x³-4x²-2x²+8x+x²-4x+2x-8-8x²+32=0
x³-13x²+6x+32=0
x²(x-2)-11x(x-2)-16(x-2)=0
(x-2)(x²-11x-16)=0
x-2=0
x=2 не удов усл
x²-11x-16=0
D=121+64=185
x1=(11-√185)/2
x2=(11+√185)/2