1) \(\left(5x-4\right)\left(4x-5\right)+\left(5x-1\right)\left(x+4\right)+3\left(3x-2\right)\)

\(=20x^2-41x+20+\left(5x-1\right)\left(x+4\right)+3\left(3x-2\right)\)

\(=20x^2-41+20+5x^2+19x-4+3\left(3x-2\right)\)

\(=20x^2-41x+20+5x^2+19x-4+9x-4\)

\(=25x^2-13x+10\)

2) \(\left(5x-4\right)^2+\left(16-25x^2\right)+\left(5x+4\right)\left(3x+2\right)\)

\(=\left(5x-4\right)^2+16-25x^2+\left(5x-4\right)\left(3x+2\right)\)

\(=25x^2-40x+16^2-25x^2+\left(5x-4\right)\left(3x+2\right)\)

\(=25x^2-40x+16^2-25x^2+15x^2-2x-8\)

\(=15x^2-42x+24\)

\(B=\left(5x-11\right)^2-\left(10x-22\right)\left(5x-9\right)+\left(5x-9\right)^2\)

\(=\left(5x-11\right)^2-2\left(5x-11\right)\left(5x-9\right)+\left(5x-9\right)^2\)

\(=\left[\left(5x-11\right)-\left(5x-9\right)\right]^2\)

\(=\left(-2\right)^2=4\)

Sửa đề:

Cách 1:

\(\left(5x-1\right)^2+2.\left(1-5x\right).\left(4+5x\right)+\left(5x+4\right)^2\)

\(=\left(1-5x\right)^2+2.\left(1-5x\right).\left(5x+4\right)+\left(5x+4\right)^2\)

\(=\left(1-5x+5x+4\right)^2\)

\(=5^2\)

\(=25\)

Cách 2:

\(\left(5x-1\right)^2+2.\left(1-5x\right).\left(4+5x\right)+\left(5x+4\right)^2\)

\(=\left(5x-1\right)^2-2.\left(5x-1\right).\left(5x+4\right)+\left(5x+4\right)^2\)

\(=\left(5x-1-5x-4\right)^2\)

\(=\left(-5\right)^2\)

\(=25\)

a) \(4x^2\left(5x^3-2x+3\right)\)

\(=20x^5-8x^3+12x^2\)

b) \(3y^2\left(4y^3+\frac{2}{3}y^2-\frac{1}{3}\right)\)

\(=12y^5+2y^4-y^2\)

c) \(\left(5x^2-4x\right)\left(x-2\right)\)

\(=5x^3-14x^2+8x\)

d) \(\left(3x-5\right)\left(2x+11\right)-\left(2x+3\right)\left(3x+7\right)\)

\(=6x^2+22x-55-6x^2-23x-21\)

\(=-x-76\)

1, \(4x^2\left(5x^3-2x+3\right)=20x^5-8x^3+12x^2\)

2, \(3y^2\left(4y^3+\frac{2}{3}y^2-\frac{1}{3}\right)=12y^5+2y^4-y^2\)

3, \(\left(5x^2-4x\right)\left(x-2\right)=5x^3-10x^2-4x^2+8x=5x^3-14x^2+8x\)

4, \(\left(3x-5\right)\left(2x+11\right)-\left(2x+3\right)\left(3x+7\right)=6x^2+33x-10x-55-\left(6x^2+14x+9x+21\right)\)

\(=6x^2+23x-55-6x^2-23x-21=-76\)

1) 4x²( 5x³ - 2x + 3 ) = 20x⁵ - 8x³ + 12x²

2) 3y²( 4y³ + 2/3y² - 1/3 ) = 12y⁵ + 2y⁴ - y² 

3) ( 5x² - 4x )( x - 2 ) = 5x³ - 14x² + 8x

4) ( 3x - 5 )( 2x + 11 ) - ( 2x + 3 )( 3x + 7 )

= 6x² + 23x - 55 - ( 6x² + 23x + 21 )

= 6x² + 23x - 55 - 6x² - 23x - 21

= -76

áp dụng hằng đẳng thức ra luôn là (1-5x+5x+4)²=5²=25

Nhầm bài nãy dễ

bài này theo sự tính toán của mình thì nó bằng 25 phải không.hihi

lên thiên đường

a: \(=5\left(4x^2-4x+1\right)+4\left(x^2+2x-3\right)-2\left(9x^2-30x+25\right)\)

\(=20x^2-20x+5+4x^2+8x-12-18x^2+60x-50\)

\(=6x^2+48x-57\)

b: \(=\left(2x^2+1\right)^2-4x^2-\left(2x^2+1\right)^2=-4x^2\)

c: \(=\left(9x-1+1-5x\right)^2=\left(4x\right)^2=16x^2\)

Q=\(\left(x-y\right)^3+x^3+3x^2y+3xy^2-\left(x-y\right)^3-3x^2y-3xy^2\)

Q=\(x^3+y^3\)

P=\(\left(5x-1-5x-4\right)^2\)

P=25

\(=16+24x+9x^2-25x^2+9=-16x^2+24x+25\)