SOLUTION: How would you go about solving this factor? Factor: 4x^2 – 81

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Question 101965: How would you go about solving this factor?
Factor: 4x^2 – 81
Answer by mathemanic(13) About Me  (Show Source):
You can put this solution on YOUR website!
+4x%5E2+-+81+
As +a%5E2+-+b%5E2+=+%28a+%2B+b%29%2A%28a+-+b%29+ so that
+4x%5E2+-+81+=+%282x+%2B+9%29%2A%282x+-+9%29+
Solution to the equation is therefore:
+%282x+%2B+9%29+%2A+%282x+-+9%29+=+0+
+x%5B1%5D+=+-9%2F2+ or +x%5B2%5D+=+9%2F2+
Cheers :)