1. \((-2)\cdot(-2)\cdot(-2)\cdot5\cdot5=-200\)
2. \(\Big(-\dfrac{3}{4}\Big)\cdot\Big(-\dfrac{3}{4}\Big)\cdot\Big(-\dfrac{3}{4}\Big)\cdot\Big(-\dfrac{3}{4}\Big)\cdot(-2)\cdot(-2)\cdot(-2)=-\dfrac{81}{32}\)
3. \(x\cdot x\cdot x\cdot x\cdot x\cdot y\cdot y\cdot y=x^5\cdot y^3\)
4. \((3x)^3=3^3\cdot x^3=27x^3\) and \(3x^3=3\cdot x^3\).
5. \((2x)^3=2^3\cdot x^3=8x^3\) and \(3(2x)=6x\) and \(8x^3\neq 6x\); thus, \((2x)^3\neq3\cdot(2x)\).