From the figure
[tex]\begin{gathered} \angle1+\angle2=180 \\ \angle3+\angle4=180 \end{gathered}[/tex]Because they are linear angles
Then the first answer is right
[tex]m\angle1+m\angle2=m\angle3+m\angle4[/tex]Since l is parallel to m, then
[tex]m\angle1+m\angle5=180[/tex]Because they are interior supplementary angles
[tex]m\angle1+m\angle5=m\angle3+m\angle4[/tex]Because both of them = 180
Then answer 2 is right
[tex]\begin{gathered} m\angle3+m\angle4=180 \\ m\angle4+m\angle7=180\text{ interior supplementary angles} \end{gathered}[/tex]Then
[tex]m\angle3+m\angle4=m\angle4+m\angle7[/tex]The last answer also is right
For answer 3
let us check it
[tex]m\angle1+m\angle6=m\angle4+m\angle6[/tex]Since angle 6 is common in the two sides, then we can cancel it from both sides, then
[tex]m\angle1=m\angle4[/tex]But no mention about that these two angles are equal, then we can not say they are equal
The wrong statement is answer 3
