Question

Question was provided via image upload.

Explanation:

Step1: Use exterior angle theorem

The exterior angle of a triangle is equal to the sum of the two non - adjacent interior angles. So, \(100=(2x + 3)+51\).

Step2: Simplify the equation

Subtract 51 from both sides: \(100-51=2x + 3\), which gives \(49=2x + 3\).

Step3: Solve for \(x\)

Subtract 3 from both sides: \(49 - 3=2x\), so \(46=2x\). Then divide both sides by 2: \(x = 23\).

Answer:

\(x = 23\)