You can put this solution on YOUR website! find the roots of the equality 6x^2+5x=4 ... 6x^2+5x-4=0 ... factoring gives (3x+4)(2x-1)=0 ... so the roots are -3/4 and 1/2
the roots are the "boundry points" between solutions ... in this case, the three ranges are <-3/4, between -3/4 and 1/2, and >1/2
test a range by choosing a value in it ... 0 is between -3/4 and 1/2 ... 6(0^2)+5(0)<4 ... 0<4 so x must be between -3/4 and 1/2
testing the other ranges will show no solution; this is because the "boundry points" are between solutions and non-solutions