Answer:
The variable expression is given by:
86*d
Explanation:
We are asked to convert the given phrase into a variable expression.
We are asked to use the letter "d" to denote the variable and "*" sign is used in place of the product or multiplication.
The phrase is:
...The product of 86 and the depth of the river...
Let d denote the depth of the river.
Hence, the conversion of the given expression into the variable form we have:
86*d