Please help with this

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?

Find the value of x for which the lines are parallel.

Solve the given system of equations. 2y= -x+9 , 3x-6= -15