Prove that the points `(a ,b+c),(b ,c+a)a n d(c ,a+b)` are collinear.

Explanation

To prove that the points \( (a, b+c) \), \( (b, c+a) \), and \( (c, a+b) \) are collinear, we will calculate the slopes between pairs of points and show that they are equal.

### Step 1: Define the points
Let:
- Point A = \( (a, b+c) \)
- Point B = \( (b, c+a) \)
- Point C = \( (c, a+b) \)

...