$2 x \color{#FF6800}{ + } \color{#FF6800}{ 1 } = 3$
$ $ Move the constant to the right side and change the sign $ $
$2 x = 3 \color{#FF6800}{ - } \color{#FF6800}{ 1 }$
$2 x = \color{#FF6800}{ 3 } \color{#FF6800}{ - } \color{#FF6800}{ 1 }$
$ $ Subtract $ 1 $ from $ 3$
$2 x = \color{#FF6800}{ 2 }$
$\color{#FF6800}{ 2 } \color{#FF6800}{ x } = \color{#FF6800}{ 2 }$
$ $ Divide both sides by the same number $ $
$\color{#FF6800}{ x } = \color{#FF6800}{ 1 }$