Explanation:
the area of a rectangle is always
length × width
so, here we have
8x³y³z⁷ × 7x³y⁸z⁴
since we don't have further information about the variables, we can't calculate a specific number, but we can simplify the result expression.
remember, factors with the same base can be combined (when multiplying terms of the same variable by different exponents, we summit add the exponents).
and multiplication is freely commutative : the sequence of factors does not matter.
8x³y³z⁷ × 7x³y⁸z⁴ = 8×7 × x³x³ × y³y⁸ × z⁷z⁴ =
= 56x⁶y¹¹z¹¹