1) x/2(x+3) -2/x=0
(x²-4(x+3)/2x(x+3)=0
x²-4x-12=0
D=b²-4ac(a=1,b=-4,c=-12)
D=16+48=64=8²
x1,x2=(-b+-корень изD)/2a
x1=(4-8)/2= -2
x2=(4+8)/2=6
2) (6(x+1)+6x)=5x(x+1)
6x+6+6x=5x²+5x
12x+6-5x²-5x=0
-5x²+7x+6=0 *(-1)
5x²-7x-6=0
D=49+120=169=13²
x1=(7-13)/10= -0.6
x2=(7+13)/10= 2
3) (x²-12-x)/x²=0
x²-x-12=0
D=1+48=49
x1=(1-7)/2= -3
x2=(1+7)/2=4
4) x(x+2)-7(x-2)-8=0
x²+2x-7x+14-8=0
x²-5x+6=0
D=25-24=1
x1=(5-1)/2=2
x2=(5+1)/2=3
5) 9/(x-3)= -9(3-x)
3x-9-x(3-x)=0
3x-9-3x+x²=0
x²-9=0
(x-3)(x+3)=0
x-3=0, x1=3, x+3=0, x2= -3
6)
2x(2x+3)-15+32x²-3x(2x-3)= =0
4x²+6x-15+32x²-6x²+9x=0
30x²+15x-15=0, :15
2x²+x-1=0
D=1+8=9=3²
x1=(-1-3)/4= -1
x2=(-1+3)/4=0.5