\(a,\left(4x-7\right)\left(16x^2+28+49\right)=\left(4x\right)^3-7^3=64x^3-343\)\(b,\left(3x+1\right)\left(9x^2-3x+1\right)-9x\left(3x^2+9x\right)\)

\(=27x^3+1-27x^3+9x=9x+1\)

19 22 25 28 5(3x + 2) – 4(2x +3) x*(1 + 2x) 4(1 + x) – 3(2x-5) 4x–8(6) - X) 23/ ... 2x” – 4x + 3x – 6 = 2x” – X-6 (b) (x-3) = (x-3)(x-3) (c) (2x+y)(2x–y) = x* = x* – 3x ... (x - 6)” 7 (3x + 5)(x-6) 8 (8x + 2)(3x + 4) (4x – 1)(2x – 3) 10 (2x +5)* 11 (8x – 3)(2x + ... 27 (4x + 3y)(x + y) 28 (2x + 5)(5x – 2) (4x – 3y)(4x + y) 30 (7x + 2y)(3x + 4y) 24/ ...

\(a)=3x\cdot\left(2x-7-4x+5\right)=3x\cdot\left(-2x-2\right)=3x\cdot\left[-2\cdot\left(x+1\right)\right]\)

Bạn ghi lại đề đi, khó nhìn quá

12x²  + 8x - 9x - 6 - 12x² + 30x + 2x -5 + 1= 31x - 10

a) \(=x^2-49-x^2\) \(=-49\)

b) \(=25x^2-1-25x^2-1\) \(=-2\)

c) \(=16x^2-1-16x^2+8x-1\) \(=8x-2\)

d) \(=9x^2-30x+25-9x^2+25\) \(=50-30x\)

N=2(2x + 5 )^2 - 3(1 + 4x )(1 - 4x)

= 2 (4x^2 + 20x + 25) - 3(1 - 16x^2)

= 8x^2 + 40x + 50 - 3 + 48x^2

= 56x^2 + 40x - 47

(.....????!!!!!!.....)

=\(-19\frac{1}{4}\)

Ta có:

2x(2x-1)²-3x(x+3)(x-3)-4x(x+1)²

=2x(4x²-4x+1)-3x(x²-9)-4x(x²+2x+1)

=8x³-8x²+2x-3x³+27x-4x³-8x²+4x

=x³-16x² +33x