Find the sum:
-1 + 9.
a. -10
b. -8
c. 8
d. 10

The Answer is C.) -1+9 is the same as 9-1 which equals 8.

Hope this helps! (:

“exterior angles of triangles. an exterior (or external) angle is the angle between one side of a triangle and the extension of an adjacent side. try this drag the orange dots on any vertex to reshape the triangle.” look to get to the answer i explained what it means and other things i hope it you .