Ответ:\(a^5\cdot a^7=a^{12}\).\(x^9:x^4=x^5\).\((b^3)^5=b^{15}\).\((xy)^4=x^4y^4\).\((2a^2)^3=8a^6\).\(a^4\cdot(a^3)^2=a^{10}\).\((c^5)^2\cdot c^3:c^7=c^6\).