Answer:
Step-by-step explanation:
The square means a [tex]90[/tex] degree angle.
We know that all the angles in a triangle add to [tex]180[/tex] degrees. So, we can build an equation for x: [tex](2x+1)+(5x+5)+(90)=180[/tex]
Combining like terms on the left side gives [tex]7x+96=180[/tex]
Subtracting [tex]96[/tex] from both sides gives [tex]7x=84[/tex]
Dividing both sides by [tex]7[/tex] gives [tex]\boxed{x=12}[/tex]
