Supplementary means that the angles have to add up to 180, so you have your equation.
180=5x+17x-18
198=22x
x=9
Then to find the measures of the angles, you plug x back in.
m∠ABD=5(9)=45 degrees
m∠BDE=17(9)-18=153-18=135 degrees
Answer:

Step-by-step explanation:
Given the expression

Follow the PEMDAS order of operations

calculate within parentheses 

calculate exponents

Multiply and divide (left to right)

Add and subtract (left to right) 

Thus,

The slope of horizontal lines is ALWAYS 0.
The answer is B. 0
58.11 i got that answer by dividing 39 by 149