Ta có $2x =5-3y$$2P = 4x^2 +3y^2 +2= (5-3y)^2+3y^2+2=12y^2 -30y+27$$=3(4y^2-10y+9)= 3 [ (2y-\dfrac{5}{2})^2 +\dfrac{11}{4}] \ge \dfrac{33}{4}$$\Rightarrow P \ge \dfrac{33}{8}$$\min P =\dfrac{33}{8}$ khi $y =\dfrac{5}{4};\ x= \dfrac{5}{8}$
Ta có $2x =5-3y$$2P = 4x^2 +3y^2 +2= (5-3y)^2+
6y^2+
4=1
5y^2 -30y+2
9$$=
15(y^2-
2y+
1)
+14=
15(y-
1)^2 +14 \ge
q14$$\Rightarrow P \ge
q \frac{
14}{
2}
=7$$\min P =
7$ khi $y =
1;\ x=
1$