Question

X and y are angles on a triangle line l forming linear pairs if twice of x is 30 degree less than y, find x and y

Answer 1

since x and y form a linear pair
there sum must be 180°

according to question ,

=> 2x+30° = y
=> x = (y-30°)/2


x+y = 180° (as x and y form a linear pair)

=> (y-30°)/2 + y = 180°

=> (y-30°)/2 +2y/2 = 180°

=> (y-30°+2y)/2 = 180°

=> (3y-30°)/2 = 180°

=> 3y-30° = 2(180°)

=> 3y = 360°+30° => 390°

y = 390°/3 => 130°


if y = 130°
then, x = (y-30°)/2
=> x = (130-30)/2

=> x = 100°/2 => 50°


we could have taken it out the easier way , as ,
x+y = 180°
=> x+130° = 180°

=> x = 50°



hope this helps

Answer 2

x+y=180
2x+30=y
substitute,
x+2x+30=180
3x=180-30
3x=150
x=150/3
x=50
y=180-50
y=130

ans-x=50
       y=130