Final answer:
In mathematical expressions, units refer to the type of measurement, like dollars for money. Lindsay's total weekly salary expression, including her base pay of $400 and a 15% commission on sales, would be expressed in dollars. The algebraic expression for her salary is T = 400 + 0.15d, where T is her total weekly salary in dollars and d is the dollar amount of her sales.
Step-by-step explanation:
To identify the units for the expression in the given question means to state the type of measurement associated with the numerical values included in the algebraic expression. In the context of Lindsay's salary, the unit for the expression will be in dollars because we are dealing with money.
First, we know that Lindsay gets a base salary of $400 per week, which is a fixed amount. Second, she receives a commission of 0.15 (or 15%) on each sale she makes. If we denote the total dollar value of sales she makes in a week as d, her commission for the week is 0.15 times d.
To write a verbal model and algebraic expression: Lindsay's total salary for the week is her base salary plus her commission on sales. Therefore, the algebraic expression will be T = 400 + 0.15d, where T represents Lindsay's total weekly salary and d represents the dollar value of sales. The unit for both terms in the expression is dollars, since the base salary and the commission are money that Lindsay earns.
It is important to check if the answer makes sense: A base salary of $400 and a 15% commission on the dollar value of sales would correctly calculate Lindsay's salary as a dollar amount, hence the units are represented correctly as dollars.