Answer:
x = - 80/17, or x = - 4 [tex]\frac{12}{17}[/tex]
Step-by-step explanation:
13x-11 +18×15+ 4x+1=180°
<=> (13x + 4x) + (18×15+ 1 - 11)=180°
<=> 17x + 260 =180
<=> 17x = 180 - 260
<=> 17x = - 80
<=> x = - 80/17
<=> x = - 4 [tex]\frac{12}{17}[/tex]
