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zaphod
how do i simplify thisl..
\[(x-2)(\frac{100}{x} - 5)\]
@ParthKohli @AccessDenied @Aadarsh
\[\begin{align} \text{F.O.I.L. = First Outside Inside Last}\\ \hline \\ &(ax+b)(cx+d)\\ \ \\ \text{First:}&(\color{blue}{ax}+b)(\color{blue}{cx}+d)\to \color{blue}{ax}\cdot\color{blue}{cx}=\color{blue}{acx^2}\\ \text{Outside:}&(\color{green}{ax}+b)(cx+\color{green}{d})\to \color{green}{ax}\cdot\color{green}{d}=\color{green}{adx}\\ \text{Inside:}&(ax+\color{red}{b})(\color{red}{cx}+d)\to \color{red}{b}\cdot\color{red}{cx}=\color{red}{bcx}\\ \text{Last:}&(ax+\color{orange}{b})(cx+\color{orange}{d})\to \color{orange}{b}\cdot\color{orange}{d}=\color{orange}{bd}\\ \hline \\ (ax+b)(cx+d)&=\color{blue}{acx^2}+\color{green}{adx}+\color{red}{bcx}+\color{orange}{bd} \end{align}\] Only difference from a typical FOIL is that you have a 1/x term, but you can still use the same exact method.
@zaphod , please proceed as instructed by @nbouscal , u will get the answer. Its easy.
wow, i like this method :D, thanks alot @nbouscal
\(\begin{align} \text{F.O.I.L. = First Outside Inside Last}\\ \hline \\ &(ax+b)(cx+d)\\ \ \\ \text{First:}&(\color{blue}{ax}+b)(\color{blue}{cx}+d)\to \color{blue}{ax}\cdot\color{blue}{cx}=\color{blue}{acx^2}\\ \text{Outside:}&(\color{green}{ax}+b)(cx+\color{green}{d})\to \color{green}{ax}\cdot\color{green}{d}=\color{green}{adx}\\ \text{Inside:}&(ax+\color{red}{b})(\color{red}{cx}+d)\to \color{red}{b}\cdot\color{red}{cx}=\color{red}{bcx}\\ \text{Last:}&(ax+\color{orange}{b})(cx+\color{orange}{d})\to \color{orange}{b}\cdot\color{orange}{d}=\color{orange}{bd}\\ \hline \\ (ax+b)(cx+d)&=\color{blue}{acx^2}+\color{green}{adx}+\color{red}{bcx}+\color{orange}{bd} \end{align}\)
Lol nathan you copied me
what about this method (ax+b)(cx+d) cx(ax+b)+d(ax+b)--------> very simple :)
Of course...nathan uses foil..I use the method you stated
oh any other methods? easier than this
That's it....all of the methods have the same intuition
They're the same method really, just different ways of looking at it. I actually prefer to use the long multiplication method, because it works for multiplying trinomials and polynomials as well.
Yeah, that's what I was meaning
Example:\[ \begin{align} &&&x+2\\ &\times&&\color{red}{x}+\color{blue}{1}\\ \hline \\ &&&\color{blue}{x+2}\\ &+&\color{red}{x^2+2}&\color{red}{x}\\ \hline \\ &&x^2+3&x+2 \end{align} \]Just like long multiplying numbers, but with polynomials instead. That's my preferred method :)