Answer: x=-6
you know that the interior angles of a triangle equal 180°. so lets find the remaining angle measure
64 + 27 = 91
180 - 91 = 89
so 89 is the third interior angle of the triangle. now let's find the exterior angle.
you know that the extended angle is supplementary; which means it will equal 180° as well. so lets add the third interior angle we just found and let's add it to the unknown expression:
89 + 97 + x = 180
186 + x = 180
-186 -186
x = -6
now it might seem wrong because x is negative and it feels like it should be positive. but let's check our answer.
64+27+89 does equal 180
and 97+(-6)+89 does equal 180
i hope this helps!
