Hello guys, I'm a bit stuck on both of these problems and I'd love it if I got help. Points A, B, C, and D are collinear and positioned in that order. Find the length indicated.

9) Find BC if CD = 10x +419, AD = 143, BC = 4x +
176, and AB = 8x + 362.

10) Find CD = 20, AB = 8x - 665, AD = 5x - 316, and BC = -301 + 4x. Find BC.

I would love to get a step by step guide on how to solve problems like these.