Question and Answers Forum

All Questions      Topic List

Algebra Questions

Previous in All Question      Next in All Question      

Previous in Algebra      Next in Algebra      

Question Number 122653 by mathocean1 last updated on 18/Nov/20

we define in base x the   number y and z by:  y=123^(−) ^(x ) and z=201^(−) ^x   1) without knowing x, write  the product x×y×z in function  of x.  2) we suppose that x+y+z=92  find x;y;z.

$${we}\:{define}\:{in}\:{base}\:{x}\:{the}\: \\ $$$${number}\:{y}\:{and}\:{z}\:{by}: \\ $$$${y}=\overline {\mathrm{123}}\:^{{x}\:} {and}\:{z}=\overline {\mathrm{201}}\:^{{x}} \\ $$$$\left.\mathrm{1}\right)\:{without}\:{knowing}\:{x},\:{write} \\ $$$${the}\:{product}\:{x}×{y}×{z}\:{in}\:{function} \\ $$$${of}\:{x}. \\ $$$$\left.\mathrm{2}\right)\:{we}\:{suppose}\:{that}\:{x}+{y}+{z}=\mathrm{92} \\ $$$${find}\:{x};{y};{z}. \\ $$$$ \\ $$

Answered by mr W last updated on 18/Nov/20

y=x^2 +2x+3  z=2x^2 +1  xyz=f(x)=x(x^2 +2x+3)(2x^2 +1)    x+y+z=x+x^2 +2x+3+2x^2 +1=3x^2 +3x+4=92  3x^2 +3x−88=0 ⇒x∉N  ⇒question wrong!

$${y}={x}^{\mathrm{2}} +\mathrm{2}{x}+\mathrm{3} \\ $$$${z}=\mathrm{2}{x}^{\mathrm{2}} +\mathrm{1} \\ $$$${xyz}={f}\left({x}\right)={x}\left({x}^{\mathrm{2}} +\mathrm{2}{x}+\mathrm{3}\right)\left(\mathrm{2}{x}^{\mathrm{2}} +\mathrm{1}\right) \\ $$$$ \\ $$$${x}+{y}+{z}={x}+{x}^{\mathrm{2}} +\mathrm{2}{x}+\mathrm{3}+\mathrm{2}{x}^{\mathrm{2}} +\mathrm{1}=\mathrm{3}{x}^{\mathrm{2}} +\mathrm{3}{x}+\mathrm{4}=\mathrm{92} \\ $$$$\mathrm{3}{x}^{\mathrm{2}} +\mathrm{3}{x}−\mathrm{88}=\mathrm{0}\:\Rightarrow{x}\notin\mathbb{N} \\ $$$$\Rightarrow{question}\:{wrong}! \\ $$

Commented by mathocean1 last updated on 18/Nov/20

okay sir

$${okay}\:{sir} \\ $$

Terms of Service

Privacy Policy

Contact: info@tinkutara.com