Answer:
x=80 deg
Step-by-step explanation:
It is known that the sum of the 3 angles of a triangle is equivalent to 180 deg (As the Triangle Sum Thm states). Therefore:
70+30+x=180
100+x=180
Subtract 100 from both sides to get x on one side, by itself:
100-100+x=180-100
Solve:
x=80 deg
