Answer :
First, you put all like terms to one side. So:
-16+3=8x+5x
Simplify:
-13=13x
Again, simplify:
-1=x.
We get -1 because we divide both sides of the equal sign by 13 to cancel out the 13 on the x side. 13 divided by -13 would be -1.
Hope I helped :)
~Sunflower UwU