The problem asks to find the size of angle $x$ given that the angles $50^\circ$, $x$, and $35^\circ$ lie on a straight line.

1. Problem Description

The problem asks to find the size of angle $x$ given that the angles $50^\circ$, $x$, and $35^\circ$ lie on a straight line.

2. Solution Steps

The sum of angles on a straight line is $180^\circ$.

Therefore, the sum of the given angles must be $180^\circ$.

We have the equation:

$50^\circ + x + 35^\circ = 180^\circ$.

Combine the known angles:

$85^\circ + x = 180^\circ$.

Subtract $85^\circ$ from both sides of the equation to isolate $x$:

$x = 180^\circ - 85^\circ$.

$x = 95^\circ$.

3. Final Answer

The size of angle $x$ is $95^\circ$.