For the first, simply plug in the value of x given (x = 2) into the equation:
So, 8 would be your answer.
For the second, the sum of x and 2 would be expressed as x + 2. Twice this sum would be written as 2(x+2). Finally, 8 less than twice that sum would be written as 2(x+2) - 8, which would be your expression.
For the last question, the coefficient refers to the number directly in front of the variable, x. So you need only to check what the x would simplify to in each equation and look for the expression where x has no coefficient (i.e., its coefficient is 1). For Hunter, the coefficient would be 15 (5 × 3x = 15x); for Michael, the coefficient would be 11 (6x + 5x = 11x); for Nate, the coefficient would be 1 (x = 1x); and for Spencer, the coefficient would be 2 (2x = 2x). Thus, Nate's expression has a coefficient of 1 when simplified.