Answer:
Step-by-step explanation: Use the Pythagorean Theorem to check this.
Remember that the squares of the lengths of the two smaller sides should be equal to the square of the bigger side.
10,11,15 = NO
5,12,13 = YES
12,15,20 = NO
16,30,34= YES
Hope this helps.
Your answer would be x = 12
The triangle sum theorem states that the 3 angles in a triangle equal 180.
Since we have a 90 degree angle shown, we can add it to the other two and set it equal to 180.
30+90+6x-12=180
108+6x=180
6x=72
x=12
The answer is the first option: y = -1/2x+8 :)