The figure given is a triangle
The total angle in a triangle is 180 degrees
The sizes of the angles given are:
[tex](5x-18)^0,\text{90}^0\text{and }23^0[/tex]
Therefore
[tex]5x-18+90+23=180[/tex]
Hence, to get x, we will collect like terms
[tex]5x=180+18-90-23[/tex]
=>
[tex]\begin{gathered} 5x=85 \\ \\ \frac{5x}{5}=\frac{85}{5} \end{gathered}[/tex]
=>
[tex]x=17[/tex]
Hence, the value of x = 17
