The answer is -11/2, 9/2
Explanation
You have to rewrite the absolute value equation as two separate equations.
2x+1=10
2x+1=-10
Then you solve for X in each equation.
2x+1=10 would give you 9/2
2x+1=-10 would give you -11/2
So your final solutions would be x1= -11/2 x2= 9/2