What is

Multply both sides of the equation by 7.

_____

When the variable is in the numerator of a proportion like this, you can solve it by multiplying by that denominator. That multiplication cancels the denominator and gives you the value of the variable.

In general, you multiply by the reciprocal of the coefficient of x. When that coefficient is 1/7, you multiply by 7/1. Of course, you know that 7/7 = 1 and that x/1 = x.

529 and 531

step-by-step explanation:

lockers 1, 4, 9, 16, 25, 40, and 49 are open

i ran through it by the other answer is wrong