4x²+x-3 = 4(x²+ 1/4 * x -3/4 ) =
= 4 (x² +x - 3/4 x - 3/4)=
= 4( x(x+1) - 3/4 (x+1))=
= 4 (x+1)(x-3/4)
(4x²-9 ) / (2x²+13x+15) =0
(2x-3)(2x+3) / (2x²+10x +3x+15) =0
(2x-3)(2x+3) / (2x(x+5) +3(x+5)) =0
(2x-3)(2x+3) / (2x+3)(x+5) =0
(2x-3) / (x+5) =0
x+5≠0
x≠-5
2x-3 =0
x=3/2
x=1.5