To solve the equation 25x + 4 = 15, one must isolate the variable, x.
First, subtract 4 from both sides of the equation:
25x + 4 - 4 = 15 - 4
This simplifies to:
25x = 11
Next, divide both sides of the equation by 25 to solve for x:
25x/25 = 11/25
This simplifies to:
x = 11/25
Thus, the solution to the equation 25x + 4 = 15 is x = 11/25.