(a+1)(a+2)(a^2+4)(a-1)(a^2+1)(a-1)
Rút gọn các biểu thức sau:4
a,(x-2)^3-x(x-1)(x+1)+6x(x-3)
b,(2x-3y^2-5)^2-(3y^2-2x+5)^2
c,(a^2-1)(a^2+a+1)(a^2-a+1)
d,(a-2)(a-1)(a-1)(a+2)(a^2+1)(a^2+4)
e,(2+1)(2^2+1)(2^4+1)(2^8+1)(2^16+1)
f,1^2-2^2+3^2-4^2+...+2015^2-2016^2
b,(1+x+x^2)(1-x)(1+x)(1-x+x^2)
c,(a+1)(a+2)(a^2+4)(a-1)(a^2+1)(a-2)
d,(-3a^3+a^6+9)(a^3+3)
e,(a^2-1)(a^2-a+1)(a^2+a+1)
e: \(\left(a^2-1\right)\left(a^2+a+1\right)\left(a^2-a+1\right)\)
\(=\left(a^3-1\right)\left(a^3+1\right)\)
\(=a^6-1\)
b: Ta có: \(\left(1+x+x^2\right)\left(1-x\right)\left(1+x\right)\left(1-x+x^2\right)\)
\(=\left(1-x^3\right)\left(1+x^3\right)\)
\(=1-x^6\)
c: \(\left(a+1\right)\left(a+2\right)\left(a^2+4\right)\left(a-1\right)\left(a^2+1\right)\left(a-2\right)\)
\(=\left(a+1\right)\left(a-1\right)\left(a^2+1\right)\left(a+2\right)\left(a-2\right)\left(a^2+4\right)\)
\(=\left(a^2-1\right)\left(a^2+1\right)\left(a^2-4\right)\left(a^2+4\right)\)
\(=\left(a^4-1\right)\left(a^4-16\right)\)
\(=a^8-17a^4+16\)
d: \(\left(a^3+3\right)\left(a^6-3a^3+9\right)\)
\(=\left(a^3\right)^3+3^3\)
\(=a^9+27\)
1/ Chứng minh các đẳng thức:
a. 1/a(a+1)=1/a-1/a+1
b. 2/a(a+1)(a+2)=1/a(a+1)-1/(a+1)(a+2)
2/ Thực hiện phép tính:
A=1/2002+2003.2001/2002-2003
3/ Thực hiện phép tính bằng cách hợp lí:
a) 11/125-17/18-5/7+4/9+17/14
b) 1-1/2+2-2/3+3-3/4+4-1/4-3-1/3-2-1/2-1
4/ Tìm x, biết:
a) 11/13-(5/42-x)=-(15/28-11/13)
b) lx+4/15l-l-3,75l=-l-2,15l
bạn tách từng câu ra. thế này k ai làm cho đâu
Dùng hằng đẳng thức để thực hiện phép tính
(a+1)×(a+2)×(a^2+4)×(a-1)×(a^2+1)×(a-2)
(a^2-1)×(a^2-a+1)×(a^2+a+1)
bài 4: (đề 2) Tìm a
a) \(2\dfrac{3}{4}-a+\dfrac{1}{4}=1\dfrac{1}{2}\) b) \(3\dfrac{1}{4}-a-1\dfrac{3}{4}=\dfrac{7}{9}\) c) \(2\dfrac{5}{6}-1\dfrac{1}{2}-a=\dfrac{1}{6}\)
a,a+1/4=2 3/4-1 1/2
a+1/2=5/4
a=5/4-1/2
a=3/4
b,a-7/4=13/4-7/9
a-7/4=89/36
a= 89/36+7/4
a=152/36
c,3/2-a=17/6-1/6
3/2-a=8/3
a= 3/2-8/3
a= -7/6
Tập hợp các ước của -8 là
A. A = 1 ; − 1 ; 2 ; − 2 ; 4 ; − 4 ; 8 ; − 8 .
B. A = 0 ; ± 1 ; ± 2 ; ± 4 ; ± 8 .
C. A = 1 ; 2 ; 4 ; 8 .
D. A = 0 ; 1 ; 2 ; 4 ; 8 .
Bài 6: Rút gọn biểu thức:
\(A=\frac{a^3-3a+\left(a^2-1\right)\sqrt{a^2-4}-2}{a^3-3a+\left(a^2-1\right)\sqrt{a^2-4}+2}\left(a>2\right)\)
\(B=\sqrt{\frac{1}{a^2+b^2}+\frac{1}{\left(a+b\right)^2}+\sqrt{\frac{1}{a^4}+\frac{1}{b^4}+\frac{1}{\left(a^2+b^2\right)^2}}}\left(ab\ne0\right)\)
Tìm a
a) \(2\dfrac{3}{4}-a+\dfrac{1}{4}=1\dfrac{1}{2}\)
b)3\(\dfrac{1}{4}-a-1\dfrac{3}{4}=\dfrac{7}{8}\)
c) 2\(\dfrac{5}{6}-1\dfrac{1}{2}-a=\dfrac{1}{6}\)
a) \(...\dfrac{11}{4}-a+\dfrac{1}{4}=\dfrac{3}{2}\)
\(\dfrac{11}{4}+\dfrac{1}{4}-a=\dfrac{3}{2}\)
\(3-a=\dfrac{3}{2}\)
\(a=3-\dfrac{3}{2}\)
\(a=\dfrac{6}{2}-\dfrac{3}{2}\)
\(a=\dfrac{3}{2}\)
b) \(...\dfrac{13}{4}-a-\dfrac{13}{4}=\dfrac{7}{8}\)
\(\dfrac{13}{4}-\dfrac{13}{4}-a=\dfrac{7}{8}\)
\(0-a=\dfrac{7}{8}\)
\(a=-\dfrac{7}{8}\) (ra số âm lớp 5 chưa học nên bạn xem lại đề)
c) \(...\dfrac{17}{6}-\dfrac{3}{2}-a=\dfrac{1}{6}\)
\(\dfrac{17}{6}-\dfrac{9}{6}-a=\dfrac{1}{6}\)
\(\dfrac{8}{6}-a=\dfrac{1}{6}\)
\(a=\dfrac{8}{6}-\dfrac{1}{6}\)
\(a=\dfrac{7}{6}\)
a, 2\(\dfrac{3}{4}\) - a + \(\dfrac{1}{4}\) = 1\(\dfrac{1}{2}\)
a = 2 + \(\dfrac{3}{4}\) + \(\dfrac{1}{4}\) - 1 - \(\dfrac{1}{2}\)
a = 2 + 1 - 1 - \(\dfrac{1}{2}\)
a = 2 - \(\dfrac{1}{2}\)
a = \(\dfrac{3}{2}\)
b, 3\(\dfrac{1}{4}\) - a - 3\(\dfrac{1}{4}\) = \(\dfrac{7}{8}\)
(3\(\dfrac{1}{4}\) - 3\(\dfrac{1}{4}\)) - a = \(\dfrac{7}{8}\)
a = - \(\dfrac{7}{8}\)
c, 2\(\dfrac{5}{6}\) - 1\(\dfrac{1}{2}\) - a = \(\dfrac{1}{6}\)
a = 2 + \(\dfrac{5}{6}\) - 1 - \(\dfrac{1}{2}\) - \(\dfrac{1}{6}\)
a = (2-1) + (\(\dfrac{5}{6}\) - \(\dfrac{1}{6}\)) - \(\dfrac{1}{2}\)
a = 1 + \(\dfrac{2}{3}\) - \(\dfrac{1}{2}\)
a = \(\dfrac{7}{6}\)
`#040911`
`a)`
\(2\dfrac{3}{4}-a+\dfrac{1}{4}=1\dfrac{1}{2}\\ \left(2\dfrac{3}{4}+\dfrac{1}{4}\right)-a=1\dfrac{1}{2}\\ 3-a=1\dfrac{1}{2}\\ a=3-1\dfrac{1}{2}\\ a=\dfrac{3}{2}\\ \text{Vậy, a = }\dfrac{3}{2}\)
`b)`
\(3\dfrac{1}{4}-a-3\dfrac{1}{4}=\dfrac{7}{8}\\ \left(3\dfrac{1}{4}-3\dfrac{1}{4}\right)-a=\dfrac{7}{8}\\0-a=\dfrac{7}{8}\\ a=0-\dfrac{7}{8} \\ a=\dfrac{-7}{8}\)
Bạn xem lại đề, lớp 5 chưa học dấu âm.
`c)`
\(2\dfrac{5}{6}-1\dfrac{1}{2}-a=\dfrac{1}{6}\\ \dfrac{4}{3}-a=\dfrac{1}{6}\\ a=\dfrac{4}{3}-\dfrac{1}{6}\\ a=\dfrac{7}{6}\\ \text{Vậy, a = }\dfrac{7}{6}.\)
Chứng minh :
a) a\(a^4 + b^4 +c^2 ≥ 2a(ab^2 -a+c+1)+a^2(1+b^2)+b^2(1+c^2)+c^2(a+a^2) ≥6abc\)
b) \(\dfrac{1}{a+b-c}+\dfrac{1}{b+c-a}+\dfrac{1}{c+a-b}\text{≥}\dfrac{1}{a}+\dfrac{1}{b}+\dfrac{1}{c}\)