We know that the sum of the angles of a triangle must be equal to 180°, with this and seen the figure, we can find the equation:
[tex](2x+11)\text{ + (51) + (90) = 180 , wich implies, (2x+11) + (51) = 90}[/tex]
Continuing the calculos:
[tex]2x\text{ + 62 = 90, wich inplies, 2x = 90 - 62, wich implies, 2x= 28}[/tex]
So, just need to divide 28 by 2, wich gives us that x=14.
