Oblicz wyrażenie dla x=[latex]1frac{1}{2}[/latex], y=[latex]-frac{1}{4}[/latex], k=[latex]-frac{3}{8}[/latex]. a)[latex]frac{x+y}{x+k}[/latex] b)[latex]frac{x-y}{y-k}[/latex] c)[latex]frac{x+y-k}{y+k}[/latex] d)[latex]frac{2x+8k}{4y-2k}[/latex]

[latex]x=1frac12; y=-frac14; k=-frac38\ \ frac{x+y}{x+k}=frac{1frac12+(-frac14)}{1frac12+(-frac38)}=frac{frac32-frac14}{frac32-frac38}=frac{frac64-frac14}{frac{12}{8}-frac38}=frac{frac54}{frac98}=frac54cdotfrac89=frac{10}{9}=1frac19\ \ frac{x-y}{y-k}=frac{frac32-(-frac14)}{-frac14-(-frac38)}=frac{frac64+frac14}{-frac28+frac38}=frac{frac74}{frac18}=frac74cdotfrac81=14\ \ [/latex] [latex]frac{x+y-k}{y+k}=frac{frac32+(-frac14)-(-frac38)}{-frac14+(-frac38)}=frac{frac{12}{8}-frac28+frac38}{-frac28-frac38}=frac{frac{13}{8}}{-frac58}=frac{13}{8}cdot(-frac85)=-frac{13}{5}=\=-2frac35\ \ frac{2x+8k}{4y-2k}=frac{2cdotfrac32+8cdot(-frac38)}{4cdot(-frac14)-2cdot(-frac38)}=frac{3-3}{-1+frac34}=0\[/latex]