Zadanie 1 :
[tex]\frac{6x+2+10x+6}{2}=4x-8 \ \ |\cdot2\\\\16x+8=8x-16\\\\16x-8x=-16-8\\\\8x=-24 \ \ |:8\\\\x=-3[/tex]
Zadanie 2 :
[tex]a_1=6, \ a_5=\frac{2}{27}\\\\a_5=a_1\cdot q^4\\\\6\cdot q^4=\frac{2}{27} \ \ |\cdot\frac{1}{6}\\\\q^4=\frac{1}{81}\rightarrow q=\frac{1}{3}[/tex]