x=5
Since line PA and line PB are both tangent to circle O, it means that they are congruent together. So you have to set the equations together
5(x-2)=2x+5
Distribute
5x-10=2x+5
Add 10 on both sides
5x=2x+15
Subtract 2x on both sides
3x=15
Divide 3 on both sides
x=5
