Question

angle AOC and angle BOC form a linear pair. if angle AOC =a , angle BOC=b and a-2b=30. find the value of a and b

Answer 1

a+b=180 (linear pair)
a=180-b

a-2b =30
180-b-2b=30
180-3b=30
180-30=3b
150=3b
50=b
b=50

Answer 2

Given

angle AOC and angle BOC form a linear pair.

angle AOC =a , angle BOC=b

and a-2b=30.

Find the  value of a and b .

To proof

As given

angle AOC and angle BOC form a linear pair

∠AOC + ∠BOC = 180°

put the value

a + b = 180

than the two equation becomes

a-2b=30 and a + b = 180

multiply  a + b = 180 by 2 and subtracted from a-2b=30

2a + 2b - 2a + 4b = 360 - 60

6b = 300

b = 50

put this in the equation a + b = 180

a + 50 =180

a = 130

the value of a = 130 and b = 50

Hence proved