Answer:
The next step should be ''add 7x''.
Explanation:
Given : If the first step in the solution of the equation
is "add 10,"
To find : What should the next step be?
Solution :
Equation

Step 1 - Add 10 both side,


Step 2 - Add 7x both side,


Step 3 - Divide both side by 2,


Therefore, The next step should be ''add 7x''.