(i) xy × yz × zx = x²y²z²(ii) a × -a² × a³ = -a⁶(iii) 2 × 4y × 8y² × 16y³ = 1024y⁶(iv) a × 2b × 3c × 6abc = 36a²b²c²(v) m × -mn × mnp = -m³n²p