Factor completely

1) 6x^2 + 42x

2) x^2 − 7x − 30

3) x^2 + 9x +20

4) x^2 - 14x +48

5) 2x^2 +21x - 11

6) 5a^2 - 125

7) 8x^2 - 6x - 9

8) 4x^2y - 24xy + 32

( I never asked a question before so yeah idk what to say)

Look at the figure below: triangle abc is a right triangle with angle abc equal to 90 degrees. the length of ac is 5 units and the length of ab is 4 units. d is a point above c. triangle adc is a right triangle with angle dac equal to 90 degrees and dc parallel to ab. what is the length, in units, of segment cd?