Step-by-step explanation:
10000-(10000n/20) = 10000 - (500n)
6500 = 10000 - 500n
3500 = 500n
n = 7
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
These lines look like the MEDIANS of each side of the triangle. A median bisects a side of the triangle (splits it exactly in half) into two equal halves. Where 3 medians of a triangle meet is termed the CENTROID of the triangle.