Another approach is to start by taking the square root of both sides.
You know that the square root of 49 is 7.
On the left-hand side, we have the square root of (x - 1)^2.
You need to know that the square root of an algebraic expression squared like (x - 1)^2 is the absolute value of the radicand.
In other words, the square-root of (x - 1)^2 is |x - 1|.
|x - 1| = 7
Now, follow the definition of absolute value, to get rid of the absolute value symbols. Then, finish by solving the two resulting equations in x.