Answer:
[tex]\huge\boxed{12x-2\dfrac{9}{10}=12x-2.9}[/tex]
Step-by-step explanation:
[tex]\left(7x-6\dfrac{1}{2}\right)-\left(-5x-3\dfrac{3}{5}\right)\\\\=7x-6\dfrac{1}{2}+5x+3\dfrac{3}{5}\qquad\text{combine like terms}\\\\=(7x+5x)+\left(-6\dfrac{1}{2}+3\dfrac{3}{5}\right)\qquad\text{find LCD}=10\\\\=12x+\left(-6\dfrac{1\cdot5}{2\cdot5}+3\dfrac{3\cdot2}{5\cdot2}\right)\\\\=12x+\left(-6\dfrac{5}{10}+3\dfrac{6}{10}\right)\\\\=12x-\left(6\dfrac{5}{10}-3\dfrac{6}{10}\right)\\\\=12x-\left(5\dfrac{10+5}{10}-3\dfrac{6}{10}\right)\\\\=12x-2\dfrac{15-6}{10}\\\\=12x-2\dfrac{9}{10}[/tex]
