Question

in the given figure AB is perpendicular to BC at B find the value of x

Answer 1

X+20+2x+1+7x-11=90
10x+10=90
10x=80
X=8

Answer 2

Seg AB is perpendicular  to Seg BC.
i.e. angle ABC=90°
now; x+20+2x+1+7x-11=90°
10x+10=90°
10x=90-10
10x=80°
hence x=80/10
           x=8