$\frac{x - 3}{6} = \frac{7}{9}$
9(x − 3) = 7 * 6
9x − 27 = 42
9x = 42 + 27
$x = \frac{69}{9} = \frac{23}{3} = 7\frac{2}{3}$

$\frac{x + 7}{3} = \frac{2x + 3}{5}$
5(x + 7) = 3(2x + 3)
5x + 35 = 6x + 9
5x − 6x = 9 − 35
−x = −26
x = 26

$\frac{2x - 3}{5} = \frac{9}{10}$
10(2x − 3) = 5 * 9
20x − 30 = 45
20x = 45 + 30
$x = \frac{75}{20} = \frac{15}{4} = 4\frac{1}{4}$

$\frac{x + 3}{2} = \frac{3x - 2}{7}$
7(x + 3) = 2(3x − 2)
7x + 21 = 6x − 4
7x − 6x = −4 − 21
x = −25