The value of r in the equation 3 = 8 - r is found by rearranging the equation to isolate r, resulting in r equals 5, which is option E. The correct option is E.
To find the value of r in the equation 3 = 8 - r, we can rearrange the equation by adding r to both sides, and then subtracting 3 from both sides to isolate r.
Step-by-step, the solution looks like this:
Add r to both sides: 3 + r = 8
Subtract 3 from both sides: r = 8 - 3
Simplify the right side: r = 5
Therefore, the value of r is 5, which corresponds to option E.