How do I solve these types of equations?

Consider a perfectly competitive market described by the following demand and supply equations:

QD=50-2P

QS=-4+P

1)Now, suppose that a $3 per unit tax is placed on buyers.As a result of this tax, consumer surplus _______________ by ____ compared to the perfectly competitive equilibrium

2) Now, suppose that a $3 per unit tax is placed on buyers. As a result of this tax, the price sellers receive is

3) Now, suppose that a $3 per unit tax is placed on buyers.As a result of this tax, the tax revenue received by the government is