jamajo Posted May 31, 2012 Share Posted May 31, 2012 Solve. (2y-3)* (2y-3)* Sorry I don't know how to do an exponent on the keyboard so * means squared. We were able to get here but no further: (4y*-12y+9)(4y*-12y+9) I actually know the answer is 16y*(4th power)-96y*(3rd power)+216y*(squared)-216y+81. I just don't know WHY! What rule am I following to solve this? Thanks for any insight. Quote Link to comment Share on other sites More sharing options...
jamajo Posted May 31, 2012 Author Share Posted May 31, 2012 Duh....I DO understand. I misunderstood my daughter's answer. She tried to perform FOIL on this problem but she can't b/c these aren't binomials they are trinomials so it works like the distributive property. Each term in the first trinomial is multiplied by each term in the 2nd trinomial then combine like terms. :blushing: Quote Link to comment Share on other sites More sharing options...
Dana Posted May 31, 2012 Share Posted May 31, 2012 And that's why I despise FOIL. It only works for binomials. It's also just a special case of the distributive property which works for all polynomial multiplication. FYI - Use the carat (shift-6) to represent an exponent: (2y-3)^2 *(2y-3)^2 would be your original problem Quote Link to comment Share on other sites More sharing options...
wapiti Posted June 1, 2012 Share Posted June 1, 2012 If this was an equation, with something on the other side of the equals sign, I'd rather try to take the square root of both sides (twice, if possible) than multiply all that out. Quote Link to comment Share on other sites More sharing options...
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