If you are solving y² + 2y = 48 by completing the square, the next line would be

Solution:

Given, y² + 2y = 48

We have to find the next step while solving y² + 2y = 48.

We need to complete the square to make LHS a trinomial. 

Now, y² + 2y + c = 48

To find c, we multiply the coefficient of y by -(1/2) and square it to get the third term.

The coefficient of y is 2. Thus 2 ×-(1/2)  1 and squaring it we get 1²

Thus the trinomial is y² + 2y+1²

We know, (a + b)² = a² + 2ab + b² 

(y+1)² = 48 +1

(y+1)² = 49

Therefore, the next step in solving is making the LHS a trinomial.

If you are solving y² + 2y = 48 by completing the square, the next line would be

Summary:

If you are solving y² + 2y = 48 by completing the square, the next line would be y² + 2y - 48 = 0.