Answer: The correct option is C.
Explanation:
In the given figure we can say that the triangle ABC is an isosceles triangle, because two sides AB and AC of the triangle are same.
In a isosceles triangle the angles corresponding to the same sides are equal. Therefore,
[tex]\angle ABC =\angle ACB=(3x+8)^{\circ}[/tex]
It is noticed that angle ABC and exterior angle B lies on a straight line it means they are supplementary angles and their sum is 180 degree.
[tex](5x+12)+(3x+8)=180[/tex]
Combine like terms.
[tex]8x+20=180[/tex]
Subtract both sides by 20.
[tex]8x=160[/tex]
Divide both sides by 8.
[tex]x=20[/tex]
The value of x is 20. Therefore the correct option is C.
