Im not sure about this one either -10=-14v+14v

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?

Give the equations of two different lines that are perpendicular to the line 3x + 4y = 7.

Don't know how to find x given these segment lengths