What is the explicit formula for the arithmetic sequence -7.5, -9, -10.5, -12, ?
O an=-7.5+(-1.5)(n-1)
O a,=-7.5+ d(-1.5-1)
o an=-1.5+(-7.5)(n-1)
o a=-1.5+0(-7.5-1)

Ineed here’s a picture of the question

Factor this polynomial completely. x^2-8x+12

Harry owes the bank money. to repay his debt, he paid $150 back to the bank each month. after 10 months, his remaining debt was $6900. what was the original amount of harry's debt? how long did it take harry to pay back his entire debt?