Question

Explain how to solve please

Answer 1

Check the picture below.

surely you know how much that is.

Answer 2

Find the measure of ED. From the theorem: an angle formed by a chord and a tangent that intersect on a circle is half the measure of the intercepted arc.

So, the answer clearly is 4x - 8 = 80/2 (80 is the angle).

To solve it take both fraction to the same denominator.

(8x - 16)/2 = 80/2

Multiply both fractions for 2 to delete denominators.

8x - 16 = 80

Move - 16 to the right of equal with changed sign.

8x = 80 + 16

8x = 96

8x/8 = 96/8

x = 12

Answer C