Use foil method
\left(3x\right)\left(3x\right)+3x\left(1\right)+\left(-1\right)\left(3x\right)+\left(-1\right)\left(1\right) 9x^2+3x-3x-1
Combine like terms
Answer\:=\:9x^2-1
Frequently asked questions (FAQs)
What is the formula to find the length of a triangle's hypotenuse given its two perpendicular sides?
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Question: What is the area of an isosceles triangle with base 12 cm and height 9 cm?