Tuần15 Tiết 29-30 Ngày 11 / 12 / 2015 Lớp 10T LESSION PLAN THE SYSTEM OF EQUATION Aim of The Lesson: a Knowledge: Students use knowledge: the system of equation and solution system of equation b Skills: Know how to solution, and applications solution system of equation c Attitude: Careful, accuracy in calculations and reasoning Positive sense of learning, creative thinking Understand and apply solution system of equation Subject Matter - Reference: Algebra - Analysis for High-school Textbook - Materials: Sheets of paper, Puzzles Procedure CONTENT Teacher and Students’ activities Exercise 1: Solve the system of equation �xy x 0(1) � x x y x y xy y 0(2) � Solution We have (2) � (2 x xy) ( x y y ) ( x y ) � (2 x y 1)( x y ) y 2x 1 � �� y x2 � By substituting y x into (1), we obtain: x3 x � x � y By substituting y x into (1), we obtain: � 1 x � 2 � x x 1 � � 1 x � � �1 � � ;� � � � � Thus, the solution set is 1;1 ; � � Gv: Cao Bảo Đằng Exercise 2: Solve the system of equation �xy x y x y (1) � � �x y y x 2( x y )(2) Solution �x �1 �y �0 Conditions: � From (1) � x ( y 1) x y y 0(*) (3 y 1)2 Therefore ,(*) has two roots x y 1; x y Since x �1 and y �0 then x y (no solution) We substitute x y into (2), we obtain: ( y 1)( y 2) y 1( does not satisfy condition) � �� y2 � Thus, the solution set is 5;2 Exercise 3: Solve the system of equation �y (5 x 4)(4 x )(1) �2 �y x xy 16 x y 16 0(2) Solution From (2), we have y (4 x 8) y x 16 x 16 0(*) b 4ac � (4 x 8) � � � 4.(5 x 16 x 16) 16 x 64 x 64 20 x 64 x 64 36 x Therefore, (*) has two roots y 4x 6x 4x 6x 5x , y 4 x 2 By substituting y=5x+4 into (1), we obtain � (5 x 4) (5 x 4)(4 x) � (5 x 4) (5 x 4)(4 x) � (5 x 4)(5 x x) � (5 x 4).6 x � 5 5x x �y0 � �� �� � x0 � x 0� y 4 � By substituting y = 4-x into (1), we obtain � (4 x) (5 x 4)(4 x) � (4 x)(4 x x 4) x 4� y 0 � �� x 0� y 4 � �4 � ; 0; ; 4;0 Thus, the solution set is � ;0 � �5 � Gv: Cao Bảo Đằng Exercise 4: Solve the system of equation x y xy (1) � �2 �x 2( xy 8) y (2) Solution We have from (2) : x xy 16 y 0(*) y 4(16 y ) y 64 y 64 Therefore, (*) has two roots y2 y2 2 y2 x y2 x By substituting x y into (1) , we obtain 4( y 4) y 4( y 4) y � y 32 y 64 y y 16 y � y 48 y 60 ( no solution) By substituting x y into (1), we obtain y2 4 y4 y2 y2 4 � y 32 y 64 y y 16 y � y 48 y 60 � y2 � � 10 � y2 � Hence, the solution set is � 10 ��2 10 � 2; ; 2; ; � ; ; ; �� � � 3 ��3 � � �� � Exercise 5: Solve the system of equation � �x y xy � � x 1 y 1 Solution �x �1 � Conditions: � y� � � We have from (1): x 2y xy � x xy y xy � x xy y 0(*) (5 y ) 4(1).(4 y ) 25 y 16 y y Therefore, (*) has two roots Gv: Cao Bảo Đằng x y (no solution) x 4y …… Gv: Cao Bảo Đằng ... 1) x y y 0(*) (3 y 1)2 Therefore ,(*) has two roots x y 1; x y Since x �1 and y �0 then x y (no solution) We substitute x y into (2), we obtain: ( y 1)( y 2)