KiÓm tra bµi cò: KiÓm tra bµi cò: 1. Thu gän ®a thøc sau vµ cho biÕt bËc cña ®a thøc: 1. Thu gän ®a thøc sau vµ cho biÕt bËc cña ®a thøc: M= ( 3x M= ( 3x 3 3 – 2x – 2x 2 2 + 5x – 6) + ( 4x + 5x – 6) + ( 4x 3 3 + 5x + 5x 2 2 – 3x + 2) – 3x + 2) 2. Thu gän ®a thøc sau vµ cho biÕt bËc cña ®a thøc: 2. Thu gän ®a thøc sau vµ cho biÕt bËc cña ®a thøc: N= ( 3x N= ( 3x 3 3 – 2x – 2x 2 2 + 5x – 6) - ( 4x + 5x – 6) - ( 4x 3 3 + 5x + 5x 2 2 – 3x + 2) – 3x + 2) TiÕt 60 TiÕt 60 Céng trõ ®a thøc mét biÕn Céng trõ ®a thøc mét biÕn VÝ dô 2: TÝnh tæng P(x) + Q(x): VÝ dô 2: TÝnh tæng P(x) + Q(x): P(x) = 2x P(x) = 2x 5 5 + 5x + 5x 4 4 – x – x 3 3 + x + x 2 2 – x – 1 – x – 1 Q(x) = - x Q(x) = - x 4 4 + x + x 3 3 + 5x + 2 + 5x + 2 P(x) = 2x P(x) = 2x 5 5 + 5x + 5x 4 4 – x – x 3 3 + x + x 2 2 – x – 1 – x – 1 Q(x) = - x Q(x) = - x 4 4 + x + x 3 3 + 5x + 2 + 5x + 2 P(x) + Q(x) =2x P(x) + Q(x) =2x 5 5 + 4x + 4x 4 4 + x + x 2 2 + 4x + 1 + 4x + 1 + ? 1. Cho hai ®a thøc: ? 1. Cho hai ®a thøc: M(x) = x M(x) = x 4 4 + 5x + 5x 3 3 – x – x 2 2 + x – 0,5 + x – 0,5 N(x) = 3x N(x) = 3x 4 4 – 5x – 5x 2 2 – x – 2,5 – x – 2,5 H·y tÝnh: M(x) + N(x) H·y tÝnh: M(x) + N(x) M(x) – N(x) M(x) – N(x) Chän ®a thøc mµ em cho lµ kÕt qu¶ ®óng: Chän ®a thøc mµ em cho lµ kÕt qu¶ ®óng: (2x 3 – 2x + 1) – (3x 2 + 4x – 1) = 2x 3 + 3x 2 – 6x + 2 2x 3 – 3x 2 – 6x +2 2x 3 – 3x 2 + 6x + 2 2x 3 – 3x 2 - 6x - 2 2x 3 – 3x 2 – 6x +2 P(x)= 2x 3 + 2x 2 - 2x + 4 Q(x)= 3x 3 - 6x 2 + 9x - 6 P(x) + Q(x) = 5x 3 - 4x 2 + 7x - 2 + Sai §óng §óng B¹n An thùc hiÖn phÐp tÝnh sau ®óng hay sai P(x)= 6x 3 - 5x 2 - 2x + 10 Q(x) = x 3 + x 2 - 9x + 12 P(x)-Q(x)=5x 3 - 4x 2 + 7x – 2 - Sai §óng Sai B¹n ChiÕn thùc hiÖn phÐp tÝnh sau ®óng hay sai P(x)= 6x 3 - 5x 2 - 2x + 10 Q(x) = x 3 + x 2 - 9x + 12 P(x)-Q(x)=5x 3 - 6x 2 + 7x – 2 - P(x)= x 4 + x 3 - 5x 2 + 2x + 5 Q(x)= - x 4 + 4x 3 + x 2 + 5x - 7 P(x) + Q(x) = 5x 3 - 4x 2 + 7x - 2 + Sai §óng §óng B¹n B×nh thùc hiÖn phÐp tÝnh sau ®óng hay sai P(x)= 2x 3 -2x - 1 Q(x)= -3x 3 + 4x 2 - 9x + 1 P(x)- Q(x)= 5x 3 - 4x 2 +7x - 2 Sai §óng §óng B¹n Th¶o thùc hiÖn phÐp tÝnh sau ®óng hay sai