1)
a) $$(-a)^5 \cdot a^3 = -a^5 \cdot a^3 = -a^{5+3} = -a^8$$
б) $$-a^5 \cdot a^3 = -a^{5+3} = -a^8$$
в) $$a^5 \cdot (-a)^3 = -a^5 \cdot a^3 = -a^{5+3} = -a^8$$
г) $$-(a^5) \cdot (-a)^3 = -a^5 \cdot (-1) \cdot a^3 = a^5 \cdot a^3 = a^{5+3} = a^8$$
2)
a) $$(x^8)^7 \cdot x^3 = x^{8\cdot7} \cdot x^3 = x^{56} \cdot x^3 = x^{56+3} = x^{59}$$
б) $$(x^8 \cdot x^7)^3 = (x^{8+7})^3 = (x^{15})^3 = x^{15\cdot3} = x^{45}$$
в) $$x^8 \cdot (x^8)^8 = x^8 \cdot x^{8\cdot8} = x^8 \cdot x^{64} = x^{8+64} = x^{72}$$
г) $$(x \cdot x^7)^7 = (x^{1+7})^7 = (x^8)^7 = x^{8\cdot7} = x^{56}$$
3)
a) $$(y^3)^4 \cdot (y^4)^3 = y^{3\cdot4} \cdot y^{4\cdot3} = y^{12} \cdot y^{12} = y^{12+12} = y^{24}$$
б) $$(y^4 \cdot y)^4 \cdot (y^4 \cdot y)^3 = (y^{4+1})^4 \cdot (y^{4+1})^3 = (y^5)^4 \cdot (y^5)^3 = y^{5\cdot4} \cdot y^{5\cdot3} = y^{20} \cdot y^{15} = y^{20+15} = y^{35}$$
в) $$(y^3)^2 \cdot (y^5 \cdot y^2)^2 = y^{3\cdot2} \cdot (y^{5+2})^2 = y^6 \cdot (y^7)^2 = y^6 \cdot y^{7\cdot2} = y^6 \cdot y^{14} = y^{6+14} = y^{20}$$
4)
a) $$c^{12} : (c^4)^3 = c^{12} : c^{4\cdot3} = c^{12} : c^{12} = c^{12-12} = c^0 = 1$$
б) $$(c^2)^9 : (c^2)^8 = c^{2\cdot9} : c^{2\cdot8} = c^{18} : c^{16} = c^{18-16} = c^2$$
в) $$(c^3 \cdot c)^4 : (c^4 \cdot c)^3 = (c^{3+1})^4 : (c^{4+1})^3 = (c^4)^4 : (c^5)^3 = c^{4\cdot4} : c^{5\cdot3} = c^{16} : c^{15} = c^{16-15} = c^1 = c$$