How do i write 15 - 1.5/d in algebraic expression?

change 1.5 to a fraction:

1.5 = 3/2

both the d and the 2 are in the denominator:

15 - 3/(2d)

that is an algebraic expression, but there are other ways to write it also:

= 15 - 3d^-1 /2 <=== with a negative exponent for the variable

= (30d - 3)/(2d) <=== with a common denominator

OR, in words, still the 1.5 is 3/2:

fifteen minus the quotient of 3 and 2d.

Depends on where you ASSUME the INVISIBLE parentheses are.