Ill give brainliest - please help ASAP - 25 points

WITH THE WORK THO PLEASE?

According to the theorem of chords intersecting inside the circle,

1) 15 * 8 = 10 * x

120 = 10x

120/10 = x

12 = x

2) 21 * 10 = 14 * x

210 = 14 x

210/14 = x

15 = x

3)10 * 4 = 5x

40 = 5x

40/5 = x

8 = x

4) 5x * 2x = 10*9

10x^2 = 90

x^2 = 90/10

x^2 = 9

x = √9

x = 3

5)3x + 3 * 3x = 10 * 18

9 x^2 + 9x = 180

dividing the whole eq. by 9

x^2 + x = 20

x^2 + x - 20 = 0

x^2 + 5x - 4x - 20 = 0

x(x + 5) - 4(x + 5) = 0

x - 4 = 0 OR x + 5 = 0

x = 4 or x = -5

The length cannot be negative, so,

x = 4

- (2, -7)

- lines r and s and lines t and u must be parallel