Add or subtract, as indicated. See Example 4. (5/12x²y) - (11/6xy)

Add or subtract, as indicated. See Example 4. ((17y + 3)/(9y + 7)) - ((-10y - 18)/(9y + 7 ))

Add or subtract, as indicated. See Example 4. (1/(x + z)) + (1/(x - z))

Add or subtract, as indicated. See Example 4. (3/a - 2) - (1/2 - a)

Add or subtract, as indicated. See Example 4. 4/(x+1) + 1/(x² - x + 1) - 12/(x³ + 1)

Add or subtract, as indicated. See Example 4. (3x)/(x² + x − 12) − x/(x² − 16) + x

Simplify each complex fraction. See Examples 5 and 6. (−4/3) ÷ (2/9)

Simplify each complex fraction. See Examples 5 and 6. (y/r) ÷ (x/y)