please help me with these three problems.

Ms. Smith invested $35,000 in two accounts, one yielding 7% Interest and the other yielding 11%. If she received a total of $3,050 in interest at the end of the your, how much did she invest in each account? The amount invented at 7% was A retail chain will buy 1100 cordless phones it the price is $10 each and 900 if the price is $20. A wholesaler will supply 950 phones at $40 each and 1450 at $60 each Assuming that the supply and demand functions are linear, find the market equilibrium point and explain what it means Markt equilibrium occurs when the number of units in and the price is $ per unit. The sum of the 2011 revenue and three times the 2008 revenue for a particular company is $2,885,7 million. The difference between the 2011 and 2008 revenues is $130.9 million. If the company's revenue between 2008 and 2011 is an increasing linear function, find the 2008 and 2011 revenues The 2008 revenue is 5 million (Type an integer or a decimal)