Answer:
x=[tex]-\frac{113}{3}[/tex]
Step-by-step explanation:
First, we need to solve the angle inside the triangle. That would be 55+40+angle measure=180
angle measure=85°
Now that we know that, we can solve for x by setting 85-3x-18 equal to 180° because these two values form a linear pair which is 180°.
Let's use some simple algebra to solve for x:
85-3x-18=180
67-3x=180
-3x=113
x=[tex]-\frac{113}{3}[/tex] or about -37.67
Hope this helps!! :)
