Your good its 80 one way you can always tell if its a triangle is if all the angles add up to 180
Step-by-step explanation:
option C is the correct answer of this question
x+19= 26
x+19-19= 26-19
x= 7
Check answer by using substitution method
x+19= 26
7+19= 26
26= 26
Answer is x= 7 (D.)