ANSWER
The sum of the given expression is,
[tex]23 {x}^{3} +14x [/tex]
EXPLANATION
The given expression is
[tex]19 {x}^{3} + (14x + 4 {x}^{3} )[/tex]
This expression is the same as
[tex]19 {x}^{3} +1 (14x + 4 {x}^{3} )[/tex]
We expand the parenthesis to obtain,
[tex]19 {x}^{3} +14x + 4 {x}^{3} [/tex]
We group the like terms to obtain,
[tex]19 {x}^{3} + 4 {x}^{3} + 14x [/tex]
Let us now combine the like terms to obtain,
[tex]23 {x}^{3} +14x [/tex]