`a, = 27x^3 - 1/8 + 8 - 27x^3`
` = 8 -1/8`
`= 63/8`
`b, = (343x^3 + 27 - 27)`
`= 343x^3`
a) Sai đề
b) (7x + 3)(49x² - 21x + 9) - 27
= (7x)³ + 3³ - 27
= 343x³ + 27 - 27
= 343x³
Rút gọn
a, (3x+2).(9x\(^2\)-6x+4)
b, (x-2y)\(^3\) -(x\(^2\)-2xy+y\(^2\))
Bài 3: Rút gọn các biểu thức sau:
1) ( x+ 3)(x2 -3x + 9) - (x3 + 54)
2) (2x + y)(4x2 + 2xy + y2 ) - (2x – y)(4x2 + 2xy + y2 )
3) (x – 1)3 – (x + 2)(x2 -2x +4) +3(x +4)(x – 4)
4) x(x + 1)(x - 1) – (x + 1)(x2 – x +1)
5) 8x3 - 5 (2x + 1)(4x2 – 4x + 1)
6) 27 + (x – 3)(x2 +3x + 9)
7) (x – 1)3 – (x +2)(x2 -2x + 4) +3(x +4)(x -4)
8) (x – 2)3 +6( x – 1)2 –(x +1)(x2 -x +1) +3x
1) (x-1)³+3(x-3)²-(x+2)(x²-2x+4)=(x+2)³-(x-3)(x²+9)-6x²+5
2) (x-5)(x+5)-(x-2)³-7x²+(x+1)(x²-x+1)=(x+3)³-(x³+9x²)
3) (x-4)³-(x+5)(x²+5x+25)=(x+2)(x-2x+4)-(x+4)³-(x-7)
4) (x+1)³-(x+3)(x²-3x+9)=(x-3)³+3(2x+1)²-(x³-5x+1)
1/rút gọn biểu thức
a)(x-4)^3 - 2x(x-5)^2 + (x-4)(x^2+4x+16)-(x-3)^3
b)(x+5)(x^2-5x+25)-(x+3)^3+(x-2)(x^2+2x+4)-(x-1)^3
c)(x+3y)^3 +(3x+2y)(9x^2-6xy+4y^2)-3(2x-y)^3
d)(3x+y)^3-(5x-y)(25x^2+5xy+y^2)+(x+2y)^3
cảm ơn mn ạ
1.tính nhanh các biểu thức sau
a) A= 532 + 106.107 + 472
b) B = 54.34 - ( 152 - 1 ).(152 + 1)
c) C= 502 - 492 + 482 -472+...... + 22 - 12
2.Rút gọn các biểu thức sau:
a,(x-3)(x2+3x+9)-(54+x3)
b,(3x+y)(9x2-3xy+y2)-(3x-y)(9x2+xy+y2)
Bài 1. Rút gọn các biểu thức sau:
a) A=(k-4)(k2+4k+16)-(128+k3)
b) B=(2m+3n)(4m2-6mn+9n2)-(3m-2n)(9m2+6mn+4n2)
Bài 4.Tìm x biết
a) (x-1)3+(2-x)(4+2x+x2)+3x(x+2)=16
b) (x+2)(x2-2x+4)-x(x2-2)=15
bài 1:
a)7x(x2-7x+3) b)(x+6)(x-7)
c)(x-8)2 d) (3x+2)2
e)(x-4)(x+4)-(5-x)2
Bài 2:
a)2(x-7)-9=10 b)(2x-5)2-x(4x-3)=2x+50
bài 2 : Rút gọn
a) x3-9x2+27x-27
b)x3+18x2+108x+216
c) a) 5(x+4)2+4(x-5)2-9(4+x)(x-4)
b)(x+1)3+(x-1)3+x3-3x(x+1)(x-1)
c)(a+b+c)2+(a+b-c)2+(2a-b)2
Tìm x , biết :
a. \(\left(x-2\right)^3-\left(x-3\right)\left(x^2+3x+9\right)+6\left(x+1\right)^2=15\)
b. \(2x^3-50x=0\)
c.\(5x^2-4\left(x^2-2x+1\right)-5=0\)
d. \(x^3-x=0\)
e. \(27x^3-27x^2+9x-1=1\)
1.Rút gọn
a,\(\left(3x-5\right)\left(9x^2+15x+25\right)\)
b,\(\left(2x+7\right)\left(x^2-14x+49\right)-2x\left(2x-1\right)\left(2x+1\right)\)
c,\(\left(4x-7\right)\left(16x^2+28x+49\right)\)\(\left(3x+1\right)\left(9x^2-3x+1\right)-9x\left(3x^2-1\right)\)
d,
