Question

#1 find the missing angle
#3 find the missing angle
#5 find the missing angle.

Explanation:

Step1: Solve #1: Use supplementary angles

The angles form a straight line ($180^\circ$). Let the missing angle be $p$.
$p + 56^\circ = 180^\circ$
$p = 180^\circ - 56^\circ = 124^\circ$

Step2: Solve #3: Use angle addition

The total angle is $96^\circ$, split into $x$ and $65^\circ$.
$x + 65^\circ = 96^\circ$
$x = 96^\circ - 65^\circ = 31^\circ$

Step3: Solve #5: Use vertical angles

Vertical angles are equal, and supplementary to $142^\circ$.
$x = 180^\circ - 142^\circ = 38^\circ$

Answer:

#1: $124^\circ$
#3: $31^\circ$
#5: $38^\circ$