Rút gọn A= (2*x-3)^ 2 -(3*x-2)*(x+3) B=(2 -3*x)^ 2 -3*(2*x-3)*(2*x+4) C=(3*x-4)^ 2 -(2*x-5)*(5*x-2) D=(x-

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Nhớ vote cho mk 5 sao nhá ????

Câu 1.

A = (2x – 3)² – (3x – 2)(x + 3) 

-> A = (4x² – 12x + 9) – [ 3x (x + 3) – 2 (x + 3)]

-> A = (4x² – 12x + 9) – (3x² + 9x – 2x – 6)

-> A = 4x² – 12x + 9 – 3x² – 9x + 2x + 6

-> A = (4x² – 3x²) + (2x – 12x – 9x) + (9 + 6)

-> A = x² – 19x + 15

Câu 2.

B = (2 – 3x)² – 3 (2x – 3)(2x + 4)

-> B = (4 – 12x + 9x²) – 3 [ 2x (2x + 4) – 3 (2x + 4)]

-> B = (4 – 12x + 9x²) – 3 (4x² + 8x – 6x – 12)

-> B = (4 – 12x + 9x²) – (12x² + 24x – 18x – 36)

-> B = 4 – 12x + 9x² – 12x² – 24x + 18x + 36

-> B = (4 + 36) + (18x – 12x – 24x) + (9x² – 12x²)

-> B = 40 – 18x – 3x²

Câu 3.

C = (3x – 4)² – (2x – 5)(5x – 2)

-> C = (9x² – 24x + 16) – [ 2x (5x – 2) – 5 (5x – 2)]

-> C = (9x² – 24x + 16) – (10x² – 4x – 25x + 10)

-> C = 9x² – 24x + 16 – 10x² + 4x + 25x – 10

-> C = (16 – 10) + (4x + 25x – 24x) + (9x² – 10x²)

-> C = 6 + 5x – x²

Câu 4.

D = (x – 3)³ – x (x + 2)(x – 2) 

-> D = (x³ – 9x² + 27x – 27) – x (x² – 4)

-> D = (x³ – 9x² + 27x – 27) – (x³ – 4x)

-> D = x³ – 9x² + 27x – 27 – x³ + 4x

-> D = (x³ – x³) – 9x² + (27x + 4x) – 27

-> D = -9x² + 31x – 27