To use the distributive property means to "distribute" the 6 among each term inside the parentheses. So we have to multiply the 6 by 5x and then multiply 6 by -3.
= 6(5x - 3)
multiply 6 by each term in parentheses
= (6 * 5x) + (6 * -3)
multiply inside each parentheses; remember a negative times a positive equals a negative
= 30x - 18
ANSWER: 30x - 18
Hope this helps! :)