a,(3x+7).(2x+3)-(3x-5).(2x+11) b,(2x+1).(x-3)-(x+4).(2x-5) c,(6x-1).(2-x)+(3x+5).(2x-1) d,3.(x-2).(x+4)-(3x+1).(x+3) ĐÂY LÀ BÀI RÚT GỌN BIỂU THỨC Ạ EM

0 bình luận về “a,(3x+7).(2x+3)-(3x-5).(2x+11) b,(2x+1).(x-3)-(x+4).(2x-5) c,(6x-1).(2-x)+(3x+5).(2x-1) d,3.(x-2).(x+4)-(3x+1).(x+3) ĐÂY LÀ BÀI RÚT GỌN BIỂU THỨC Ạ EM”

1. `a,(3x+7).(2x+3)-(3x-5).(2x+11)`

   ` = (6x^2 + 9x + 14x + 21) – (6x^2 + 33x – 10x – 55)`

   ` = 6x^2 + 9x + 14x + 21 – 6x^2 – 33x + 10x + 55`

   ` = (6x^2 – 6x^2) + (9x+14x – 33x+10x) + (21+55)`

   ` = 76`

   `b,(2x+1).(x-3)-(x+4).(2x-5)`

   ` = (2x^2 – 6x + x – 3)-(2x^2 – 5x + 8x-20)`

   ` = 2x^2 – 6x + x – 3 – 2x^2 + 5x – 8x + 20`

   ` = (2x^2- 2x^2) + (-6x + x + 5x-8x) + (20-3)`

   ` = -8x + 17`

   `c,(6x-1).(2-x)+(3x+5).(2x-1)`

   ` = (12x – 6x^2 – 2 + x) + (6x^2 – 3x + 10x – 5)`

   ` = 12x – 6x^2 – 2 + x + 6x^2 – 3x + 10x – 5`

   ` = (6x^2- 6x^2)+ (12x + x – 3x + 10x) – (2+5)`

   ` = 20x – 7`

   `d,3.(x-2).(x+4)-(3x+1).(x+3)`

   ` = (3x-6).(x+4) – (3x+1).(x+3)`

   ` = (3x^2 + 12x – 6x – 24) – (3x^2 + 9x + x + 3)`

   ` = 3x^2 + 12x-6x-24 – 3x^2 – 9x-x-3`

   ` = (3x^2 – 3x^2) + (12x-6x – 9x-x) – (24+3)`

   ` = -4x – 27`

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2. `a)(3x+7)(2x+3)-(3x-5)(2x+11)`

   `=(6x^2+23x+21)-(6x^2+23x-55)`

   `=6x^2+23x+21-6x^2-23x+55`

   `=(6x^2-6x^2)+(23x-23x)+(21+55)`

   `=76`

   `b)(2x+1)(x-3)-(x+4)(2x-5)`

   `=(2x^2-5x-3)-(2x^2+3x-20)`

   `=2x^2-5x-3-2x^2-3x+20`

   `=(2x^2-2x^2)+(-5x-3x)+(20-3)`

   `=-8x+17`

   `c)(6x-1)(2-x)+(3x+5)(2x-1)`

   `=(-6x^2+13x-2)+(6x^2+7x-5)`

   `=-6x^2+13x-2+6x^2+7x-5`

   `=(-6x^2+6x^2)+(13x+7x)-(2+5)`

   `=20x-7`

   `d)3(x-2)(x+4)-(3x+1)(x+3)`

   `=(3x^2+6x-24)-(3x^2+10x+3)`

   `=3x^2+6x-24-3x^2-10x-3`

   `=(3x^2-3x^2)+(6x-10x)-(24+3)`

   `=-4x-27`

    

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