a=[tex]1989^{2} [/tex] -1989-1988=1989(1989-1)-1988=1989*1988-1988=1988(1989-1)=1988*1988[tex] \frac{x}{1988} /4= \frac{497}{1988*1988} [/tex] ---->
x = [tex] \frac{1988/4*497}{ 1988^{2} } = \frac{ 497^{2} }{ 1988^{2} } =( \frac{497}{1988} )la puterea2= \frac{1}{4} ^{2} = \frac{1}{16} [/tex]
