Rút gọn biểu thức:
a) (2x + 1)2 + (2x - 1)2 - 2(x - 3)2
b) (x - 1)2 - (3x + 2)2
c) (6x + 1)2 + (6x - 1)2 - 2(1 + 6x) (6x - 1)
Rút gọn biểu thức:
a) (2x + 1)2 + (2x - 1)2 - 2(x - 3)2
b) (x - 1)2 - (3x + 2)2
c) (6x + 1)2 + (6x - 1)2 - 2(1 + 6x) (6x - 1)
a: \(\left(2x+1\right)^2+\left(2x-1\right)^2-2\left(x-3\right)^2\)
\(=4x^2+4x+1+4x^2-4x+1-2\left(x^2-6x+9\right)\)
\(=8x^2+2-2x^2+12x-18\)
\(=6x^2+12x-16\)
b: \(\left(x-1\right)^2-\left(3x+2\right)^2\)
\(=x^2-2x+1-9x^2-12x-4\)
\(=-8x^2-14x-3\)
c: \(\left(6x+1\right)^2+\left(6x-1\right)^2-2\left(6x+1\right)\left(6x-1\right)\)
\(=\left(6x+1\right)^2-2\left(6x+1\right)\left(6x-1\right)+\left(6x-1\right)^2\)
\(=\left(6x+1-6x+1\right)^2=2^2=4\)
rút gọn biểu thức
(6x +1) ^2 +(6x-1)^2-2(1+6x)(6x-1)
x(2x^2-3)-x^2(5x+1)+x^2
3x(x-2)-5x(1-x)-8(x^2-3)
\(\left(6x+1\right)^2+\left(6x-1\right)^2-2\left(1+6x\right)\left(6x-1\right)\)
\(=\left(6x+1\right)^2-2\left(6x+1\right)\left(6x-1\right)+\left(6x-1\right)^2\)
\(=\left(6x+1-6x+1\right)^2\)
\(=4\)
\(x\left(2x^2-3\right)-x^2\left(5x+1\right)+x^2\)
\(=2x^3-3x-5x^3-x^2+x^2\)
\(=\left(2x^3-5x^3\right)+\left(x^2-x^2\right)-3x\)
\(=-3x^3-3x\)
\(3x\left(x-2\right)-5x\left(1-x\right)-8\left(x^2-3\right)\)
\(=3x^2-6x-5x+5x^2-8x^2+24\)
\(=\left(3x^2+5x^2-8x^2\right)-\left(6x+5x\right)+24\)
\(=-11x+24\)
rút gọn biểu thức
(6x +1) ^2 +(6x-1)^2-2(1+6x)(6x-1)
x(2x^2-3)-x^2(5x+1)+x^2
3x(x-2)-5x(1-x)-8(x^2-3)
rút gọn biểu thức
(6x +1) ^2 +(6x-1)^2-2(1+6x)(6x-1)
x(2x^2-3)-x^2(5x+1)+x^2
3x(x-2)-5x(1-x)-8(x^2-3)
Bài 1: Tính:
a) x2(x-2x3); b) (x2+1)(5-x); c) (x-2)(x2+3x-4); d) (x-2)(x-x2+4); e) (x2-1)(x2+2x); f) (2x-1)(3x+2)(3-x)
Bài 2: Tính:
a) (x-2y)2; b) (2x2+3)3; c) (x-2)(x2+2x+4); d) (2x-1)3
Bài 3: Rút gọn biểu thức:
a) (6x+1)2+(6x-1)2-2(1+6x)(6x-1); b) 3(22+1)(24+1)(28+1)(216+1); c) x(2x2-3)-x2(5x+1)+x2; d) 3x(x-2)-5x(1-x)-8(x2-3)
Bài 4: Tính nhanh:
a) 1012; b) 97.103; c) 772+232+77.46; d) 1052-52; e) A= (x-y)(x2+xy+y2)+2y3 tại x= \(\dfrac{2}{3}\) và y= \(\dfrac{1}{3}\)
Bạn chú ý đăng lẻ câu hỏi! 1/
a/ \(=x^3-2x^5\)
b/\(=5x^2+5-x^3-x\)
c/ \(=x^3+3x^2-4x-2x^2-6x+8=x^3=x^2-10x+8\)
d/ \(=x^2-x^3+4x-2x+2x^2-8=3x^2-x^3+2x-8\)
e/ \(=x^4-x^2+2x^3-2x\)
f/ \(=\left(6x^2+x-2\right)\left(3-x\right)=17x^2+5x-6-6x^3\)
rút gọn biểu thức
a)(x+y)^2-(x-y)^2
b)2.(x+y).(x-y)+(x+y)^2+(x-y)^2
c)(x+3).(x^2-3x+9)-(54+x^3)
d)(2x+y).(4x^2-2xy+y^2)-(2x-y)
e)(6x+1)^2+(6x-1)^2-2.(6x+1).(6x-1)
f)(a-b)^3-(a+b)^3+2b^3
câu c (x+3)(x^2-3x+9)-(54+x^3)=x^3+27-54-x^3
=27
Bài 1: Rút gọn các biểu thức sau:
a, A = (x-2).(2x-1) - 2x (x+3)
b, B = (3x-2).(2x+1) - (6x-1).(x+2)
c, C = 6x.(2x+3) - (4x-1).(3x-2)
d, D = (2x+3).(5x-2)+(x+4).(2x-1) - 6x.(2x-3)
Bài 2: Chứng tỏ rằng các đa thức không phụ thuộc vào biến.
a, 2x(3x-5).(x+11) - 3x.(2x+3).(x+7)
b, (x2+5x-6).(x-1) - (x+2).(x2-x+1) - x(3x-10)
c, (x2+x+1).(x-1) - x2(x+1) + x2 - 5
Bài 1
A= (x-2)(2x-1)-2x(x+3)=2x2-x-4x+2-2x2-6x=-11x+2
Bài 1:
a) \(A=\left(x-2\right)\left(2x-1\right)-2x\left(x+3\right)\)
\(A=2x^2-x-4x+2-2x^2-6x\)
\(A=-11x+2\)
b) \(B=\left(3x-2\right)\left(2x+1\right)-\left(6x-1\right)\left(x+2\right)\)
\(B=6x^2+3x-4x-2-6x^2-12x+x+2\)
\(B=-12x\)
c) \(C=6x\left(2x+3\right)-\left(4x-1\right)\left(3x-2\right)\)
\(C=12x^2+18x-12x^2+8x+3x-2\)
\(C=29x-2\)
d) \(D=\left(2x+3\right)\left(5x-2\right)+\left(x+4\right)\left(2x-1\right)-6x\left(2x-3\right)\)
\(D=10x^2-4x+15x-6+2x^2-x+8x-4-12x^2+18x\)
\(D=36x-10\)
Bài 2:
a: Ta có: \(2x\left(3x-5\right)\left(x+11\right)-3x\left(2x+3\right)\left(x+7\right)\)
\(=2x\left(3x^2+33x-5x-55\right)-3x\left(2x^2+14x+3x+21\right)\)
\(=6x^3+56x^2-110x-6x^2-51x^2-63x\)
\(=-117x\)
b: Ta có: \(\left(x^2+5x-6\right)\left(x-1\right)-\left(x+2\right)\left(x^2-x+1\right)-x\left(3x-10\right)\)
\(=x^3+4x^2-11x+6-\left(x^3-x^2+x+2x^2-2x+2\right)-3x^2+10x\)
\(=x^3+x^2-x+6-x^3-x^2+x-2\)
=4
c: Ta có: \(\left(x^2+x+1\right)\left(x-1\right)-x^2\left(x+1\right)+x^2-5\)
\(=x^3-1-x^3-x^2+x^2-5\)
=-6
rút gọn biểu thức
(6x +1) ^2 +(6x-1)^2-2(1+6x)(6x-1)
x(2x^2-3)-x^2(5x+1)+x^2
3x(x-2)-5x(1-x)-8(x^2-3)
ai nhanh sẽ tik
(6x+1)2+(6x-1)2-2(1+6x)(6x-1)=(6x+1+1-6x)2=4
x(2x2-3)-x2(5x+1)+x2=2x3-3x-5x3-x2= -3x3-x2-3x
3x(x-2)-5x(1-x)-8(x2-3)=3x2-6x-5x+5x2-8x2+24= -11x+24
chưa chắc là đúng đâu nhé
Bài 1:Tính:
a)(1/27.x^3-y^3)
b)(2x^2-3y^3)
bài 2:Rút gọn biểu thức:
a)(6x+1)^2+(6x-1)^2-2.(1+6x).(1+6x)
b)3(2^2+1).(2^2-1).(2^8+1).(2^16+1)
c)C=12(5^2+1).(5^4+1).(5^8+1).(5^16+1)
giúp mk vx, mk cần gấp...T^T
Bài 1 không có cơ sở để tính biểu thức.
Bài 2:
a.
$(6x+1)^2+(6x-1)^2-2(6x+1)(6x-1)$
$=[(6x+1)-(6x-1)]^2=2^2=4$
b.
$3(2^2+1)(2^4+1)(2^8+1)(2^{16}+1)$
$=(2^2-1)(2^2+1)(2^4+1)(2^8+1)(2^{16}+1)$
$=(2^4-1)(2^4+1)(2^8+1)(2^{16}+1)$
$=(2^8-1)(2^8+1)(2^{16}+1)$
$=(2^{16}-1)(2^{16}+1)=2^{32}-1$
c.
$2C=(5^2-1)(5^2+1)(5^4+1)(5^8+1)(5^{16}+1)$
$=(5^4-1)(5^4+1)(5^8+1)(5^{16}+1)$
$=(5^8-1)(5^8+1)(5^{16}+1)$
$=(5^{16}-1)(5^{16}+1)=5^{32}-1$
$\Rightarrow C=\frac{5^{32}-1}{2}$