A) find the value of x. show algebraic support.
hint: (n - 2)180

17

Step-by-step explanation:

The sum of all the angles of this polygon is

(n-2)180

Where m is the number of corners

(5-2)180

3*180

540

Hence

Sum of all angles=540

139+92+71+9x+5x=540

302+14x=540

14x=540-302

14x=238

Dividing both sides by 14

x=17

answer: bea's uncle is 25 years old.

step-by-step explanation:

given the equation , we can say that the variable "x" represents the age of bea's uncle. then to find his age, we need to solve for "x":

we must add 15 to both sides of the equation:

now we need to divide both sides of the equation by 3:

therefore, we can conclude that bea's uncle is 25 years old.