Answer:
The value of x is 3.
Step-by-step explanation:
It is given that the angles of a triangle are 128, 5x+10 and 9x.
According to the angle sum property of a triangle, the sum of all interior angles of a triangle is 180 degrees.
[tex]128+5x+10+9x=180[/tex]
[tex]138+14x=180[/tex]
[tex]14x=180-138[/tex]
[tex]14x=42[/tex]
Divide both sides by 14.
[tex]x=3[/tex]
Therefore the value of x is 3.
