ax=bx+c.

Both sides are equal,

If we change one, they will still be equal if we change both in the exact same way.

Subtract bx from both sides to bring the x parts together.

ax-bx=bx-bx+c.

ax-bx=c.

X is common in ax-bx, so we write it as x(a-b).

It's like 5(3)-3(3)=(5-3)3 or 7(4)-2(4)=(7-2)4.

So, x(a-b)=c.

Now, divide both sides by (a-b).