Question

What is the value of X?

Answer 1

45 as all angles in a triangle add up to 180. So equation is
180-(80+55)=x
Which solves to 45

Answer 2

x = 45

Explanation:

The 3 angles of a triangle add up to 180

<a + <b + <c = 180

substitute what you know

55+ 80 + <c = 180

combine like terms

135 + <c = 180

subtract 135 from each side

<c = 180 -135

<c = 45

x = 45