Hi!
To simplify expressions, we have to add like terms. Like terms are terms with the same variable and exponent, but the coefficient doesn't matter.
d and 0.06d are like terms, because they both have the variable d. Therefore we just add the coefficients together.
Note: "d" has the coefficient of 1, because there is no number by it.
1 + 0.06 = 1.06
Therefore your simplified expression is 1.06d
Hope this helps! :D
