Answer:
Y = 170, Z = 64.
Step-by-step explanation:
Since y is the external angle to x, which you got right, it is in fact, 180-10, = 170 degrees. And since z is the external to our unknown angle, that means it is equal to the sum of the other two angles in the triangle. That means z is 54 + 10, which is 64.
9(-6x-2)-7(-10x-2)
Simplify, by distributing the 9 and the -7
-54x-18+70x+14
Combine like terms
16x-4 is the simplified expression
Hope this helped!