First, subtract color(red)(2) from each side of the equation to isolate the radical while keeping the equation balanced:
sqrt(7k + 2) + 2 - color(red)(2) = 5 - color(red)(2)
sqrt(7k + 2) + 0 = 3
sqrt(7k + 2) = 3
Next, square both sides of the equation to eliminate the radical while keeping the equation balanced:
(sqrt(7k + 2))^2 = 3^2
7k + 2 = 9
Then, subtract color(red)(2) from each side of the equation to isolate the k term while keeping the equation balanced:
7k + 2 - color(red)(2) = 9 - color(red)(2)
7k + 0 = 7
7k = 7
Now, divide each side of the equation by color(red)(7) to solve for k while keeping the equation balanced:
(7k)/color(red)(7) = 7/color(red)(7)
(color(red)(cancel(color(black)(7)))k)/cancel(color(red)(7)) = 1
k = 1