How do you say 2 to the power of 3 as an xponent

Which expression is equivalent to (3^2)^-2 a.-81 b.-12 c.1/81 d.1/12

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?

Solve for b. ab + c= d b= a + old ob=allc-ch b= (d-c/a