In these questions, they're asking you to express x in terms of the other algebra.
So we can simply solve this by imaging them as real numerical values.
rx - sx + y = b
First shift +y to the other side, change it to negative.
rx - sx =b - y
Factories rx - sx by picking out the common factor x.
x ( r - s) = b - y
Shift (r-s) to the other side, and we're done.
x = b - y / r - s
Therefore, the final answer is
