Explanation:
adding all the angles then equate it to 180
x-5+2x+2x-10=180
5x-15=180
5x=195
x=39
to check, plugin x which is 39 into the given angles.
like, 39-5=34 and 2(39)=78 and 2(39)-10= 68
and all of this must be equal to 180 because the angle in a triangle is always 180 degrees.
So, 34+78+68=180