When you take the square root of $64$, think about both numbers whose square is $64$, not just one of them.

After you find the possible values for $x+1$, what do you need to do to isolate $x$ in each case?

You will get two values for $x$. Reread the question and decide which one fits the condition given about $x$.

In Desmos, type y = (x + 1)^2 on one line and y = 64 on another line so you can see where the parabola and the horizontal line intersect.

Use your cursor (or tap) to select each intersection point of the two graphs; Desmos will display the coordinates $(x,y)$ of these points.

Look at the $x$-coordinates of the intersection points and note which one is positive; that positive $x$-value is the solution the question is asking for.

Start with the equation $(x+1)^2 = 64$.

To undo the square, take the square root of both sides. Remember that when you take the square root of a squared expression, you must include both the positive and negative roots:

This means there are two possible equations to solve: $x+1 = 8$ and $x+1 = -8$.

Now solve each of the two linear equations by isolating $x$:

From $x+1 = 8$:

From $x+1 = -8$:

So the equation has two solutions: one positive and one negative.

The problem specifically asks for the positive value of $x$ that satisfies the equation.

From the two solutions, $7$ is positive and $-9$ is negative.

So the positive value of $x$ that satisfies $(x+1)^2 = 64$ is 7.