To find the value of x, we need to solve the equation 2x + 5 = 21.
First, subtract 5 from both sides of the equation:
2x + 5 - 5 = 21 - 5
2x = 16
Next, divide both sides of the equation by 2 to isolate x:
(2x)/2 = 16/2
x = 8
So, the solution to the equation 2x + 5 = 21 is x = 8.