+ + + += − + = −X 2 X 2 X 2B) P= ⇔8 2 X =10⇔ X = ⇔ =5 X 25( )2
3 )a x
2
−4x+ = ⇔4 6 x−2 = ⇔ − =6 x 2 6;x− = − ⇔ =2 6 x 8;x= −4( )
+ + + + + − − = ≥ −3
2
b x x x x x x2
−4x+ = ⇔4 6 x−2 = ⇔ − =6 x 2 6;x− = − ⇔ =2 6 x 8;x= −43
2
b x x x x x x