Alright, let's start by simplifying.
[tex]-5x+10x+3=5x+6[/tex]
Let's get all of the variables on one side.
Subtract 5x from each side to clear the right.
[tex]-5x-5x+10x+3=6[/tex]
We could also subtract out that 3...
[tex]-5x-5x+10x=3[/tex]
Combining like terms!
If we have 10x, and then subtract 5x and 5x...we're left with zero!
[tex]0=3[/tex]
However, this equation can't be true!
Since this always boils down to 0=3 (the variables don't even matter)...
There are no solutions for x that could even make the equation true!