Question

Darnelle drew this figure and the accompanying equations.

https://imgur.com/GceyTGF

w + x + y = 180
y + z = 180

Which equation must also be true?

A. w + z = 180

B. w + x + z = 180

C. y – x = w

D. w + x = z

Answer 1

@mhchen

Answer 2

y + z = 180

You can rewrite that as: y = 180 - z

Plug that into this: w + x + y = 180
so it becomes: w + x + (180-z) = 180

Simplify that out:
w + x - z = 0
so
w + x = z