Answer:
-27a³b⁶ + 8a⁹b¹²
Step-by-step explanation:
Every term in the expression above every term is a perfect cube.
In the first term (-27a³b⁶), -27 is a perfect cube of -3 while the exponents of a and b are both divisible by three.
In the second term (8a⁹b¹²),8 is a perfect cube of 2 while the exponents of a and b are divisible by three.
If the index of a number is divisible by three to give a whole number, the result of finding the cube root is a whole number hence a perfect cube root.