Please help !

solve the equation −4x^2− 12x− 9 = 0

Subtract 8 1/6 - 4 5/6 . simplify the answer and write as a mixed number.

Find the total area for the regular pyramid ( follow the answer set up in the picture)

Amerchant has coffee worth $60 a pound that she wishes to mix with 50 pounds of coffee worth $90 a pound to get a mixture that she will sell for $70 a pound. how many pounds of the & 60 coffee should be used?