Odpowiedź:
[tex]a)\ \ 2(y+6)-4(y-6)=2y+12-4y+24=-2y+36\\\\\\dla\ \ y=\frac{1}{2}\\\\-2y+36=-\not2*\frac{1}{\not2}+36=-1+36=35\\\\\\\\b)\ \ 4(x-y)-(-x+y)=4x-4y+x-y=5x-5y\\\\\\dla\ \ x=\frac{3}{2}\ \ ,\ \ y=-1\\\\5x-5y=5*\frac{3}{2}-5*(-1)=\frac{15}{2}+5=7\frac{1}{2}+5=12\frac{1}{2}[/tex]
