Answer:
x = -7y/(4 +5y)
Explanation:
You can treat y as though it were a constant. As in any 2-step linear equation, you separate the variable term(s) from the constant term, then divide by the coefficient of the variable.
4x +5xy = -7y . . . . . subtract 7y
x(4 +5y) = -7y . . . . . factor out x, so we can see its coefficient
x = -7y/(4 +5y) . . . . divide by the coefficient of x