Answer: [tex]79^{\circ}[/tex]
Step-by-step explanation:
Given
[tex]\angle M=x+20^{\circ}[/tex]
[tex]\angle N=99^{\circ}[/tex]
[tex]\angle M[/tex] and [tex]\angle N[/tex] are vertical opposite angles
[tex]\therefore \angle M=\angle N[/tex]
[tex]\Rightarrow (x+20)^{\circ}=99^{\circ}\\\Rightarrow x=(99-20)^{\circ}\\\Rightarrow x=79^{\circ}[/tex]
Thus, the value of x is [tex]79^{\circ}[/tex]
