Answer:
x=65
Step-by-step explanation:
First, we need to find the 2 base angles of the triangle
105 is adjacent to another angle, and they are on a straight line. Therefore they are supplementary and add to 180 degrees
105+z=180
Subtract 105 from both sides
z=75
140 is adjacent to another angle, and they are on a straight line. Therefore they are supplementary and add to 180 degrees
140+y=180
Subtract 140 from both sides
y=40
Now, we know the two base angles of the triangle are 40 and 75. The angles in a triangle add to 180 degrees, so
40+75+x=180
Combine like terms by adding 40 and 75
115+x=180
Subtract 115 from both sides
x=65
