Equivalent expression of -5.8c+4.2-3.1+1.4c

Factor and solve to find roots x squared -x - 90 =0

Y+ 2/y is it a polynomial in one variable or not? and if so, why?

There are a total sales of 2,000 dollars on monday on tuesday sales dropped 10% on wednesday sales dropped another 20% compared with tuesday from wednesday to thursday sales increases by an equal amount to 25% of monday total sales what is the net change in dollars on total sales from monday to tuesday