x=\frac{1}{2} , y=1,5=\frac{15}{10}=\frac{3}{2}
{x^3 - y^2=(\frac{1}{2})^3-1,5^2=(\frac{1}{2})^3-(\frac{3}{2})^2=\frac{1^3}{2^3}-\frac{3^2}{2^2}=\frac{1}{8}-\frac{9}{4}=\frac{1}{8}-\frac{18}{8}=-(\frac{18}{8}-\frac{1}{8})=-\frac{17}{8}=-2\frac{1}{8}}
=-2,125
II sposób
x^3 - y^2=(\frac{1}{2})^2-1,5^3=0,5^3-2,25=0,25-2,25=0,125-2,25=-2,125