Mathematical equation of one variable, for example, 5Y = 50 + 4Y, when the solution contains unknowns on the left, how does its sign change when it moves over People's education press grade 7 Volume 1 mathematics Chapter 5 equation of one dollar, because I have to do homework

Mathematical equation of one variable, for example, 5Y = 50 + 4Y, when the solution contains unknowns on the left, how does its sign change when it moves over People's education press grade 7 Volume 1 mathematics Chapter 5 equation of one dollar, because I have to do homework

When a number is moved to the other side of the equation, the sign is reversed, positive becomes negative, negative becomes positive
The original formula can be changed to 5y-4y = 50
∴ y=50