The value of x in the triangle with angles 80, 40 and (13x - 5) degrees is 5.
Sum of angle in a triangle
The sum of angle in a triangle is equals to 180 degrees. Recall a triangle have three sides. Therefore,
80 + 40 + 13x - 5 = 180
120 - 5 + 13x = 180
115 + 13x = 180
subtract 115 from both sides of the equation
115 - 115 + 13x = 180 - 115
13x = 65
divide both sides by 13
13x / 13 = 65 / 13
x = 5
learn more on triangle here: https://brainly.com/question/15268683
