The angle shown in the picture is a right angle, divided into two by a line segment. This line segment determined two complementary angles with measure (6x+5)º and (4x+5)º.
As mentioned both angles are complementary angles so they add up to 90º, with this in mind you can write the following expression
[tex](6x+5)+(4x+5)=90[/tex]
To simplify the expression you have to order the like terms together and then solve the operations between them:
[tex]\begin{gathered} 6x+4x+5+5=90 \\ 10x+10=90 \end{gathered}[/tex]
So the equation that can be used to find the value of x is
[tex]10x+10=90[/tex]
