$\color{#FF6800}{ a } \color{#FF6800}{ b } \left ( \color{#FF6800}{ 4 } \color{#FF6800}{ a } \color{#FF6800}{ + } \color{#FF6800}{ b } \right ) - \left ( 3 a b - b ^ { 2 } \right ) a$
$ $ Organize the expression with the distributive law $ $
$\color{#FF6800}{ 4 } \color{#FF6800}{ a } ^ { \color{#FF6800}{ 2 } } \color{#FF6800}{ b } + \color{#FF6800}{ a } \color{#FF6800}{ b } ^ { \color{#FF6800}{ 2 } } - \left ( 3 a b - b ^ { 2 } \right ) a$
$4 a ^ { 2 } b + a b ^ { 2 } \color{#FF6800}{ - } \left ( \color{#FF6800}{ 3 } \color{#FF6800}{ a } \color{#FF6800}{ b } \color{#FF6800}{ - } \color{#FF6800}{ b } ^ { \color{#FF6800}{ 2 } } \right ) a$
$ $ Change the symbol of each term in parentheses when there is a (-) symbol in front of parentheses $ $
$4 a ^ { 2 } b + a b ^ { 2 } + \left ( \color{#FF6800}{ - } \color{#FF6800}{ 3 } \color{#FF6800}{ a } \color{#FF6800}{ b } \color{#FF6800}{ + } \color{#FF6800}{ b } ^ { \color{#FF6800}{ 2 } } \right ) a$
$4 a ^ { 2 } b + a b ^ { 2 } + \left ( \color{#FF6800}{ - } \color{#FF6800}{ 3 } \color{#FF6800}{ a } \color{#FF6800}{ b } \color{#FF6800}{ + } \color{#FF6800}{ b } ^ { \color{#FF6800}{ 2 } } \right ) \color{#FF6800}{ a }$
$ $ Organize the expression with the distributive law $ $
$4 a ^ { 2 } b + a b ^ { 2 } \color{#FF6800}{ - } \color{#FF6800}{ 3 } \color{#FF6800}{ a } ^ { \color{#FF6800}{ 2 } } \color{#FF6800}{ b } + \color{#FF6800}{ a } \color{#FF6800}{ b } ^ { \color{#FF6800}{ 2 } }$
$\color{#FF6800}{ 4 } \color{#FF6800}{ a } ^ { \color{#FF6800}{ 2 } } \color{#FF6800}{ b } \color{#FF6800}{ + } \color{#FF6800}{ a } \color{#FF6800}{ b } ^ { \color{#FF6800}{ 2 } } \color{#FF6800}{ - } \color{#FF6800}{ 3 } \color{#FF6800}{ a } ^ { \color{#FF6800}{ 2 } } \color{#FF6800}{ b } \color{#FF6800}{ + } \color{#FF6800}{ a } \color{#FF6800}{ b } ^ { \color{#FF6800}{ 2 } }$
$ $ Organize the similar terms $ $
$\left ( \color{#FF6800}{ 4 } \color{#FF6800}{ - } \color{#FF6800}{ 3 } \right ) \color{#FF6800}{ a } ^ { \color{#FF6800}{ 2 } } \color{#FF6800}{ b } \color{#FF6800}{ + } \left ( \color{#FF6800}{ 1 } \color{#FF6800}{ + } \color{#FF6800}{ 1 } \right ) \color{#FF6800}{ a } \color{#FF6800}{ b } ^ { \color{#FF6800}{ 2 } }$
$\left ( \color{#FF6800}{ 4 } \color{#FF6800}{ - } \color{#FF6800}{ 3 } \right ) \color{#FF6800}{ a } ^ { \color{#FF6800}{ 2 } } \color{#FF6800}{ b } + \left ( 1 + 1 \right ) a b ^ { 2 }$
$ $ Organize the mononomial expression $ $
$\color{#FF6800}{ a } ^ { \color{#FF6800}{ 2 } } \color{#FF6800}{ b } + \left ( 1 + 1 \right ) a b ^ { 2 }$
$a ^ { 2 } b + \left ( \color{#FF6800}{ 1 } \color{#FF6800}{ + } \color{#FF6800}{ 1 } \right ) \color{#FF6800}{ a } \color{#FF6800}{ b } ^ { \color{#FF6800}{ 2 } }$
$ $ Arrange the constant term $ $
$a ^ { 2 } b + \color{#FF6800}{ 2 } \color{#FF6800}{ a } \color{#FF6800}{ b } ^ { \color{#FF6800}{ 2 } }$