Question

20.
$75^circ$ $(2x - 5)^circ$

Explanation:

Step1: Identify supplementary angles

The two angles form a straight line, so they are supplementary (sum to $180^\circ$).
$75 + (2x - 5) = 180$

Step2: Simplify the left side

Combine constant terms.
$75 - 5 + 2x = 180$
$70 + 2x = 180$

Step3: Isolate the variable term

Subtract 70 from both sides.
$2x = 180 - 70$
$2x = 110$

Step4: Solve for x

Divide both sides by 2.
$x = \frac{110}{2}$

Answer:

$x = 55$