[tex](x,6) \\
x_1=x \\
y_1=6 \\ \\
(10,-3) \\
x_2=10 \\ y_2=-3 \\ \\
\hbox{the slope: } m=\frac{y_2-y_1}{x_2-x_1}=\frac{-3-6}{10-x}=\frac{-9}{10-x} \\ \\
m=-\frac{3}{2} \\
\Downarrow \\
-\frac{3}{2}=\frac{-9}{10-x} \\
-\frac{3}{2}(10-x)=-9 \\
10-x=-9 \times (-\frac{2}{3}) \\
10-x=3 \times 2 \\
10-x=6 \\
-x=6-10 \\
-x=-4 \\
\boxed{x=4}[/tex]
