Giáo án Đại số 7 - Period 57: Plus, except mode (Cộng, trừ đa thức)

Nội dung text: Giáo án Đại số 7 - Period 57: Plus, except mode (Cộng, trừ đa thức)

1. Writing date:: Teaching's Day: Period 57: PLUS, EXCEPT MODE I. Objectives: - Students know to add and subtract polynomials. - Train skills to remove parentheses, reduce polynomials, convert polynomial. II. Prepare: - Teacher: Side board, paper checker. - Students: paper, felt pen III. Process of the lecture: 1. Stable organization: (1 ') 2. Check out the old post: (9 ') - Student 1: Please remove parentheses in the following two expressions:a/ ( 5x2 – 3y + 2) + ( 4y – 2x2 – 2 ) b/ ( 5x2 – 3y + 2) – ( 4y – 2x2 – 2 ) - Student 2: Please reduce the following polynomia: 5x2 – 3y + 2 + 4y – 2x2 – 2 Give two polynomials: A = 5x2 – 3y + 2 và B = 4y – 2x2 – 2 A + B = ( 5x2 – 3y + 2) + ( 4y – 2x2 – 2 ) A – B = ( 5x2 – 3y + 2) – ( 4y – 2x2 – 2 ) 3. Teaching new lessons: Activities of teachers Activities of students Writing tables 1.Add 2 polynomials (10 ') For 2 polynomials: - Teachers put the - Student: + Remove Add two polynomials: example content up. parentheses (with '' + '' A = 5x2 – 3y + 2 và in front) B = 4y – 2x2 – 2 + Apply commutative A B 5x2 3y 2 4y 2x2 2 and combined =5x2 -3y+2+4y-2x2 -2 properties. 2 2 + Collapse of identical 5x 2x 3y 4y 2 2 ? Please explain my categories. steps. =3x2+y - Students discuss in We say: The polynomial 3x2+y is the groups and do sum of two polynomials A and B paperwork ?1 - Class comment. - Ask students to do?
2. - Teachers collect the - Students record 2. Subtract two polynomials (13 ' paper from 3 groups and For 2 polynomials: give it up P = 5x 2 y - 4xy 2 + 5x - 3 - Students pay close 1 attention Q = xyz - 4x 2 y + xy 2 + 5x - 2 - The teacher put the 2 2 exercise up. P - Q = (5x y - 4xy + 5x - 3) - 1 - Teachers raised to - (xyz - 4x 2 y + xy 2 + 5x - ) subtract 2 polynomials 2 P-Q we do the - HS: remove = 5x 2 y - 4xy 2 + 5x - 3 - xyz + following: parentheses and reduce 1 + 4x 2 y - xy 2 - 5x + the polynomial. 2 ? Follow me how to get - 1 student takes up the 1 P - Q worksheet = 9x 2 y - 5xy 2 - xyz - 2 2 - Weak students repeat ?2 ? Recall the rule to the rule to remove remove parentheses. parentheses. - Groups discuss and make papers on paper. - Teachers ask students - Comment. to do? 2 in groups. - Teachers collect 3 lessons from 3 groups. 4. Strengthening training: (10 ') - Teachers ask 2 students to go to the board to do exercise 29 (tr40-SGK) a) (x + y) + (x - y) = x + y + x - y = 2x b) (x + y) - (x - y) = x + y - x + y = 2y - Requires exercise 32: P + (x2 - 2y2 ) = x2 - y2 + 3y2 -1 P = (x2 - y2 + 3y2 -1) - (x2 - 2y2 ) P = x2 - y2 + 3y2 -1- x2 + 2y2 P = 4y2 -1 - Give students a map of thinking system of lesson knowledge. 5. Study guide at home: (2 ') - Review the knowledge of the lesson. - Doing exercises 31, 33 (tr40-SGK) - Doing exercises 29, 30 (p13, 14-SBT)