[tex]\displaystyle\bf\\(x-4)(x+3)-(x-1)(x-3)=\\\\\\=x\cdot x+x\cdot 3-4\cdot x-4\cdot 3-\Big(x\cdot x-x\cdot 3-1\cdot x-1\cdot(-3)\Big)=\\\\\\=x^{2} +3x-4x-12-\Big(x^{2} -3x-x+3\Big)=\\\\\\=x^{2} -x-12-x^{2} +4x-3=3x-15\\\\\\x=1\frac{1}{9} =\frac{10}{9} \\\\\\3x-15=3\cdot\frac{10}{9} -15=\frac{10}{3} -15=3\frac{1}{3} -15=-11\frac{2}{3}\\\\\\Otvet \ : \ -11\frac{2}{3}[/tex]