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