There are x people in the bus. When the bus stops y people get off and 6 people get on. How many people are yhere now on the bus ?

x = 6- y

Is my answer right ?

There are x people in the bus. When the bus stops y people get off and 6 people get on. How many people are yhere now on the bus ?

x = 6- y

Is my answer right ?

Right

You want an expression for the number of people on the bus.
From the information given it would be:
No of people on bus = x - y + 6

You gave an "equation" which makes no sense
e.g. suppose there were 20 people on the bus, and 9 got off and 6 got on

so x=20, and y = 9

your equation would say

20 = 6 - 9
Does that make sense to you?

So I repeat,
no of people on the bus = x - y + 6