In this equation we have two terms: [tex](15 {x}^{4} + 10x)[/tex] and [tex] - 12( {x}^{4} + 4x)[/tex].
We need to first distribute the second one's coefficient: [tex] - 12 \times {x}^{4} - 12 \times 4x[/tex]
Simplify: [tex] - 12 {x}^{4} - 48x[/tex]
Now let's add the first part again: [tex]15 {x}^{4} + 10x - 12 {x}^{4} - 48x[/tex]
Combine the like terms: [tex]3 {x}^{4} - 38x[/tex] is your solution.
