Hey there! I'm happy to help!
The perimeter is the distance around a shape. To find, it, you add up all of the sides.
4x+3x-6+(-x)+10
To add this all up, let's first add all of the terms with x.
4x+3x-x
7x-x
6x
And we add up the constants.
-6+10
4
Therefore, the perimeter of this triangle is 6x+4.
Have a wonderful day! :D