[14/9: 2/121]x3/77
( 14/9: 2/121)x 3/77
`@` `\text {Ans}`
`\downarrow`
\(\left(\dfrac{14}{9}\div\dfrac{2}{121}\right)\times\dfrac{3}{77}\)
`=`\(\left(\dfrac{14}{9}\times\dfrac{121}{2}\right)\times\dfrac{3}{77}\)
`=`\(\left(\dfrac{7}{9}\times121\right)\times\dfrac{3}{77}\)
`=`\(\dfrac{847}{9}\times\dfrac{3}{77}=\dfrac{11}{3}\times1=\dfrac{11}{3}\)
(14/9:2/121) x 3/77
= ( 7/9 x 121/) x 3/77
= 847/9 x 3/77
=11/3 x 1=11/3
Đố vui :
1+6-2+9-55+77 . 88 : 44 : 2 . 11 : 121
1+6-2+9-55+77 . 88 : 44 : 2 . 11 : 121
= 1+6-2+9-55+7
= -34
\(1+6-2+9-55+77.88:44:2.11:121=-41+7=-34\)
A = 3/1 x 2 + 3/2 x3 + 3/3 x 4 + 3/4 x 5 + .............. + 3/9 x 10 + 77/2 x 9 + 77/9 x 6 + 77/16 x 23 + ...............+ 77 /93x 100
Giup mk nha!!!!!!! Ban nao tra loi nhanh thi mk tk cho nha!!!!!!!!! >-<
a) (x3 – x2 + x)(121 – 25y2 – 10y) – (x3 – x2 + x) – (121 – 25y2 – 10y) +1
X4 – 14x3 + 71x2 – 154x + 120
Giúp mik với ạ!!!!
a) (x3 – x2 + x)(121 – 25y2 – 10y) – (x3 – x2 + x) – (121 – 25y2 – 10y) +1
b) X4 – 14x3 + 71x2 – 154x + 120
Giúp mik vs
a: \(\left(x^3-x^2+x\right)\left(121-25y^2-10y\right)-\left(x^3-x^2+x\right)-\left(121-25y^2-10y\right)+1\)
\(=\left(x^3-x^2+x\right)\left(120-25y^2-10y\right)-\left(120-25y^2-10y\right)\)
\(=\left(120-25y^2-10y\right)\left(x^3-x^2+x-1\right)\)
\(=-\left[\left(25y^2+10y+1\right)-121\right]\left[x^2\left(x-1\right)+\left(x-1\right)\right]\)
\(=-\left(5y-10\right)\left(5y-12\right)\left(x-1\right)\left(x^2+1\right)\)
\(=-5\left(y-2\right)\left(5y-12\right)\left(x-1\right)\left(x^2+1\right)\)
b: \(x^4-14x^3+71x^2-154x+120\)
\(=x^4-5x^3-9x^3+45x^2+26x^2-130x-24x+120\)
\(=\left(x-5\right)\left(x^3-9x^2+26x-24\right)\)
\(=\left(x-5\right)\left(x^3-4x^2-5x^2+20x+6x-24\right)\)
\(=\left(x-5\right)\left(x-4\right)\left(x^2-5x+6\right)\)
\(=\left(x-5\right)\left(x-4\right)\left(x-3\right)\left(x-2\right)\)
a ]24 giờ 9 phút :3
b ] 5 phút 18 giây : 2
c ]15,6 phút : 6 + 1,27 phút x3
d ] 2 giờ 14 phút x3
e ] 14 phút 42 giây x 2
a) 24 giờ 9 phút : 3 = 8 giờ 3 phút
b) 5 phút 18 giây : 2 = 2 phút 39 giây
c)15,6 phút : 6 + 1,27 phút x 3 = 2,6 phút + 3,81 phút = 6,41 phút
d) 2 giờ 14 phút x 3 = 6 giờ 42 phút
e) 14 phút 42 giây x 2 = 29 phút 24 giây
mới học lớp 4 thôi
Bài 2: Tính nhanh:
a) \(\dfrac{3}{4}\cdot\dfrac{8}{9}\cdot\dfrac{15}{16}\cdot\dfrac{24}{25}\cdot.....\cdot\dfrac{120}{121}\cdot\dfrac{143}{144}\)
b)\(\dfrac{5}{9}\cdot\dfrac{21}{25}\cdot\dfrac{45}{49}\cdot\dfrac{77}{81}\cdot.....\dfrac{357}{361}\cdot\dfrac{437}{441}\)
ai làm đúng mk dùng 3nick mk tick cho :))))
a) \(A=\dfrac{3}{4}.\dfrac{8}{9}.\dfrac{15}{16}.\dfrac{24}{25}.....\dfrac{120}{121}.\dfrac{143}{144}\)
= \(\dfrac{1.3.2.4.3.5.4.6....10.12.11.13}{2^2.3^2.4^2.5^2...11^2.12^2}\)
= \(\dfrac{1.2.12.13}{2^2.12^2}=\dfrac{13}{2.12}=\dfrac{13}{24}\)
b) \(B=\dfrac{5}{9}.\dfrac{21}{25}.\dfrac{45}{49}.\dfrac{77}{81}....\dfrac{357}{361}.\dfrac{437}{441}\)
= \(\dfrac{1.5.3.7.5.9.7.11.....17.21.19.23}{3^2.5^2.7^2....19^2.21^2}=\dfrac{1.3.21.23}{3^2.21^2}\)
= \(\dfrac{23}{3.21}=\dfrac{23}{63}\)
1. (x2 - 9x + 20)(x2 - 13x + 12) = 1680
2. (x2 + x - 2)(x2 + x - 3) = 12
3. (x2 - 9)2 = 12x + 1
4. x3 + 3x2 + 4x + 2 = 0
5. x3 + 2x2 - x - 2 = 0
cac ban giup minh voi a
2: \(\Leftrightarrow\left(x^2+x\right)^2-5\left(x^2+x\right)-6=0\)
\(\Leftrightarrow x^2+x-6=0\)
=>(x+3)(x-2)=0
=>x=-3 hoặc x=2
5: \(\Leftrightarrow\left(x+2\right)\left(x-1\right)\left(x+1\right)=0\)
hay \(x\in\left\{-2;1;-1\right\}\)
Bài 1. Đặt tính rồi tính.
13 355 – 9 324 23 216 + 12 452
14 77 + 2 119 62 102 – 23 701
13 355 - 9 324 = 4031
23 216 + 12 452 = 35668
1477 + 2 119 = 3596
62 102 - 23 701 = 38401