Hệ phương trình X2 - X3 = m

2X2 + 2X2 + 7X3 =2

X1 + X2 +4X3 =-3

X1,X2,X3=?

1) what is the measure of the exterior angle, ∠uvw ? 2) in triangle man, what is the measure of the exterior angle at n (in degrees)?