Find the value of x in the triangle shown below.

We know that the sum of all the interior angles of a triangle is 180^o.

∴ In △ABC,

∠A + ∠B + ∠C = 180^o

⇒ (5x − 60^o) + (2x + 40^o) + (3x − 80^o) = 180^o

⇒ 10x − 100^o = 180^o 

⇒ 10x = 180^o + 100^o

⇒ 10x = 280^o

⇒ x = 28^o

Hence, the value of x is 28^o.