We want to complete the square for the given expression. To do so, we will first identify b. In a quadratic expression, b is the linear coefficient, which is the number that is multiplied by the x-variable.
x^2-18x+c ⇔
x^2+( -18)x+cNow, we will calculate ( b2)^2. Since we have that b=-18, we can calculate the value of ( b2)^2 by substituting -18 for b.