(6x-1)(1+6x)+14<7x(2+5x)
6x+36x^2-1-6x+14<14x+35x^2<br> 36x^2-35x^2-14x+13<0<br> x^2-14x+13<0<br> D=196-52=144 x1=(14+12)/2*1=26/2=13 x2=(14-12)/2*1=2/2=1 (1;13)