Make an equation, solve it, and do self-check.

A collection of 109 coins is made up of quarters, dimes, and nickels. There are 7 fewer dimes than quarters and 3 less than five times as many nickels as dimes. Find the amount of the collection.

PLEASE ALSO MAKE AN EQUATION

A33 gram sample of a substance that's used to detect explosives has a k-value of 0.1473. n = noekt no = initial mass (at time t = 0) n = mass at time t k = a positive constant that depends on the substance itself and on the units used to measure time t = time, in days

Luke started a weight-loss program. the first week, he lost x pounds. the second week, he lost pounds less than times the pounds he lost the first week. the third week, he lost 1 pound more than of the pounds he lost the first week. liam started a weight-loss program when luke did. the first week, he lost 1 pound less than times the pounds luke lost the first week. the second week, he lost 4 pounds less than times the pounds luke lost the first week. the third week, he lost pound more than times the pounds luke lost the first week.

In which direction does the left side of the graph of this function point? a(x) = 3x - x2 + 4x - 2