What is the simplified from of 7(5x - 6)

Two blends of tea are mixed to make a blend that will be sold at the fair. black tea sells for $2.20 per pound and orange pekoe tea sells for $3.00 per pound. how much of each should be used to obtain a 4lb blend selling for $2.50 per pound?

Haley buys 9 pounds of apples for $3. how many pounds of apples can she buy for $1?

How many sides does a regular polygon have if each exterior angle measure is 45 degrees explain your answer, i really don't understand this.