The possible values for the missing number that make the given expression the square of a binomial is; 81
We are given the expression;
x² + 18x
Squaring that gives us;
x² ± 2ax + b²
Comparing this expression to the one we are given we can say that;
±2ax = 18x
±a = 18/2
a = ±9
Thus,we will have;
(x + 9)² as our expression which is;
x² + 18x + 81
Therefore, the missing number is 81.
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