00:05We'll use the shortened multiplication formulas to expand the parentheses
00:24Square root equals the number itself
00:28Calculate the square of half
00:32Isolate X
00:38And this is the solution to the question
Step-by-Step Solution
To solve the equation (x+21)(x−21)=0, we can apply the zero-product property, which tells us that if a product of two factors is zero, at least one of the factors must be zero.
Let us proceed with each factor:
First Factor: x+21=0
Solving for x, subtract 21 from both sides: x=−21
Squaring both sides, we get: x=(−21)2=41.
However, since the square root should be zero or positive, this case does not yield a real solution.
Second Factor: x−21=0
Solving for x, add 21 to both sides: x=21
Squaring both sides, we have: x=(21)2=41.
Therefore, the solution to the equation (x+21)(x−21)=0 is x=41.
Upon reviewing the provided choices, the correct answer that matches our solution is: 41 (Option 2).