[tex]Look\ at\ the\ picture.\\\\127^o+z=180^o\ \ \ \ \ |subtract\ 127^o\ from\ both\ sides\\\\z=53^o\\\\z+x+7^o+2x=180^o\\\\53^o+3x+7^o=180^o\\\\60^o+3x=180^o\ \ \ \ \ |subtract\ 60^o\ from\ both\ sides\\\\3x=120^o\ \ \ \ \ \ |divide\ both\ sides\ by\ 3\\\\x=40^o\\\\m\angle A=2\times40^o=80^o[/tex]
