Tolong bantu mr.crussader ^_^

Kiri:
[tex]\displaystyle f(x)=\frac{8}{5-x},x\neq 5 \\ \\ a. \\ f(1)=\frac{8}{5-1}=\frac{8}{4}=2 \\ b. \\ f(-3) = \frac{8}{5-(-3)}=\frac{8}{8}=1 \\ c. \\ f(7)=\frac{8}{5-7}=\frac{8}{-2}=-4 \\ d. \\ f(x)=2 \\ \frac{8}{5-x}=2 \\ 8=2(5-x) \\ 8=10-2x \\ 2x=10-8 \\ 2x=2 \\ x=1 \\ \\ e.\\ f(a)=0.5=\frac{1}{2} \\ \frac{8}{5-a}=\frac{1}{2} \\ 2\times 8=5-a \\ 16=5-a \\ a=5-16 \\ a=-11[/tex]

Kanan:
[tex]\displaystyle y=\frac{x-1}{2x+1},x\neq -\frac{1}{2} \\ \\ 2xy+y=x-1 \\ 2xy-x=-y-1 \\ x(2y-1)=-y-1 \\ x=\frac{-y-1}{2y-1},y\neq \frac{1}{2} \\ $Syarat : $x\neq-\frac{1}{2}$ dan $y\neq \frac{1}{2}[/tex]