c)
[tex]z=\frac{(x^{2} -y)*3}{4}|*4\\4z=(x^{2} -y)*3|:3\\ \frac{4}{3}z=x^{2} -y|+y\\ \frac{4}{3}z+y=x^{2} \\x=\sqrt{ \frac{4}{3}z+y}[/tex]
b)
[tex]k=(a+2)*c|:c\\\frac{k}{c}=a+2|-2\\ \frac{k}{c}-2=a[/tex]
