4. а) \(c^{10}:(c^2)^5\); б) \((c^3)^7:(c^3)^6\); в) \((c^2\cdot c)^3:(c^3\cdot c)^2\).

а) \(c^{10}:(c^2)^5=c^{10}:c^{10}=1\), если \(c\ne0\).

б) \((c^3)^7:(c^3)^6=c^{21}:c^{18}=c^3\), если \(c\ne0\).

в) \((c^2\cdot c)^3:(c^3\cdot c)^2=(c^3)^3:(c^4)^2=c^9:c^8=c\), если \(c\ne0\).