How would i solve this

Question

Points A, B, and C are collinear and positioned in that order. Draw a picture and solve for x if AB = 3x, BC = 2x – 12, and AC = 58.

Answer 1

First what do we know? We know that the three points are on the same line and

1. The length of AB is 3x
2. The length of BC is 2x-12
3. The length of the total line is AC which is 58

So, the total length of the line is AC = AB + BC; thus, 58 = (3x)+(2x-12)

Now, combine like terms: 58 = 5x-12

Next, add 12 to both sided: 70 = 5x

Finally, divide both sides by 5: 14 = x