Answer: -7n-3
Step-by-step explanation: first bring the 5n down then multiply -3x4n gives you -12 and multiply 5x1 that gives you 5 so you would write (5n−12n)−3
then remove the parentheses combine like terms like 5 and 12 are alike because of the n's that means subtract because of the - sign 5-12 which gives you -7 and then you bring down -3 because it's outside the parentheses and that's the answer.
