tính giá trị của mỗi biểu thức A,B,C,D rồi sắp xếp các kết quả tìm được theo thứ tự tăng dần:
A=\(\dfrac{5}{4}.\left(5-\dfrac{4}{3}\right).\left(-\dfrac{1}{11}\right)\) B=\(\dfrac{3}{4}:\left(-12\right).\left(-\dfrac{2}{3}\right)\)
C=\(\dfrac{5}{4}:\left(-15\right).\left(-\dfrac{2}{5}\right)\) D=\(\left(3\right).\left(\dfrac{2}{3}-\dfrac{5}{4}\right):\left(-7\right)\)
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
![](https://rs.olm.vn/images/avt/0.png?1311)
A=\(\dfrac{5}{4}\).(5-\(\dfrac{4}{3}\)).(\(-\dfrac{1}{11}\))
= \(\dfrac{5}{4}\).\(\dfrac{11}{3}\).(\(-\dfrac{1}{11}\))
=\(\dfrac{5}{4}\).[\(\dfrac{11}{3}.\left(-\dfrac{1}{11}\right)\text{]}\)
=\(\dfrac{5}{4}.\dfrac{1}{3}\)
=\(\dfrac{5}{12}\) (1)
B=\(\dfrac{3}{4}:\left(-12\right).\left(-\dfrac{2}{3}\right)\) =\(\dfrac{3}{4}:\text{[}\left(-12\right).\left(-\dfrac{2}{3}\right)\text{]}\)
=\(\dfrac{3}{4}:8\) =\(\dfrac{3}{4}.\dfrac{1}{8}\)=\(\dfrac{3}{32}\)(2)
C=\(\dfrac{5}{4}:\left(-15\right).\left(-\dfrac{2}{5}\right)\) =\(\dfrac{5}{4}:\text{[}\left(-15\right).\left(-\dfrac{2}{5}\right)\text{]}\)
=\(\dfrac{5}{4}:6=\dfrac{5}{4}.\dfrac{1}{6}=\dfrac{5}{24}\left(3\right)\)
D=(-3).\(\left(\dfrac{2}{3}-\dfrac{5}{4}\right):\left(-7\right)\) =(-3).\(\left(-\dfrac{7}{12}\right)\):(-7)=\(\dfrac{7}{4}:\left(-7\right)\)=\(\dfrac{7}{4}\).\(\left(\dfrac{-1}{7}\right)\)=\(\dfrac{-1}{4}\) (4)
Từ (1),(2),(3)và(4)=>Ta có thể sắp xếp các kết quả trên theo thứ tự tăng dần là:
(Bạn tự làm nhé! mình bận đi học rồi)
![](https://rs.olm.vn/images/avt/0.png?1311)
Vì A= \(\frac{605}{36}\)
B=\(\frac{-1}{24}\)
C=\(\frac{-1}{30}\)
D= \(\frac{-1}{4}\)
tức là : A= \(\frac{6050}{360}\)
B=\(\frac{-15}{360}\)
C=\(\frac{-12}{360}\)
D=\(\frac{-90}{360}\)
nÊN được sắp xếp theo thứ tự tăng dần là B < C < D < A
D=
![](https://rs.olm.vn/images/avt/0.png?1311)
\(A=\dfrac{5}{4}\left(5-\dfrac{4}{3}\right)\left(-\dfrac{1}{11}\right)\)
\(A=\dfrac{5}{4}.\dfrac{11}{3}.\left(-\dfrac{1}{11}\right)\)
\(A=-\dfrac{5}{12}\)
\(B=\dfrac{3}{4}:\left(-12\right).\left(-\dfrac{2}{3}\right)\)
\(B=\dfrac{3}{4}.\left(-\dfrac{1}{12}\right).\left(-\dfrac{2}{3}\right)\)
\(B=\dfrac{1}{24}\)
\(C=\dfrac{5}{4}:\left(-15\right).\left(-\dfrac{2}{5}\right)\)
\(C=\dfrac{5}{4}.\left(-\dfrac{1}{15}\right).\left(-\dfrac{2}{5}\right)\)
\(C=\dfrac{1}{30}\)
\(D=\left(-3\right)\left(\dfrac{2}{3}-\dfrac{5}{4}\right):\left(-7\right)\)
\(D=\left(-3\right)\left(-\dfrac{7}{12}\right)\left(-\dfrac{1}{7}\right)\)
\(D=-\dfrac{1}{4}\)
Sắp xếp theo thứ tự tăng dần:
\(A,D,C,B\)
![](https://rs.olm.vn/images/avt/0.png?1311)
Sau khi thực hiện phép tính ta được kết quả các giá trị:
\(A=\dfrac{1}{3}\) \(B=-5\dfrac{5}{12}\) \(C=-0,22\)
Sắp xếp: \(-5\dfrac{5}{12}< -0,22< \dfrac{1}{3}\) tức là \(B< C< A\)
Khi tính xong giá trị biểu thức A , B và C ta được kết quả như sau :
\(A=\dfrac{1}{3}\) ; \(B=-5\dfrac{5}{12}\); \(C=-0,22\)
Sắp xếp : \(B< C< A\)\(\left(-5\dfrac{5}{12}< -0,22< \dfrac{1}{3}\right)\)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(A=\dfrac{2}{3}+\dfrac{-1}{3}=\dfrac{1}{3}\\ B=\dfrac{25}{11}\times\dfrac{13}{12}\times\dfrac{-11}{5}=\dfrac{5\times13\times\left(-1\right)}{1\times12\times1}=\dfrac{-65}{12}\\ C=\left(\dfrac{3}{4}-\dfrac{1}{5}\right)\times\left(\dfrac{2}{5}-\dfrac{4}{5}\right)=\dfrac{11}{20}\times\dfrac{-2}{5}=\dfrac{-11}{50}\)
\(B< -1< C< 0< A\\ \Leftrightarrow B< C< A\)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(a,\left(7+3\dfrac{1}{4}-\dfrac{3}{5}\right)+\left(0,4-5\right)-\left(4\dfrac{1}{4}-1\right)\)
\(=\left(7+\dfrac{13}{4}-\dfrac{3}{5}\right)-\dfrac{23}{5}-\left(\dfrac{17}{4}-1\right)\)
\(=7+\dfrac{13}{4}-\dfrac{3}{5}-\dfrac{23}{5}-\dfrac{17}{4}+1\)
\(=\left(7+1\right)+\left(\dfrac{13}{4}-\dfrac{17}{4}\right)-\left(\dfrac{3}{5}+\dfrac{23}{5}\right)\)
\(=8-\dfrac{4}{4}-\dfrac{26}{5}\)
\(=7-\dfrac{26}{5}\)
\(=\dfrac{9}{5}\)
\(b,\dfrac{2}{3}-\left[\left(-\dfrac{7}{4}\right)-\left(\dfrac{1}{2}+\dfrac{3}{8}\right)\right]\)
\(=\dfrac{2}{3}-\left(-\dfrac{7}{4}-\dfrac{1}{2}-\dfrac{3}{8}\right)\)
\(=\dfrac{2}{3}-\left(-\dfrac{14}{8}-\dfrac{4}{8}-\dfrac{3}{8}\right)\)
\(=\dfrac{2}{3}-\left(-\dfrac{21}{8}\right)\)
\(=\dfrac{2}{3}+\dfrac{21}{8}\)
\(=\dfrac{79}{24}\)
\(c,\left(9-\dfrac{1}{2}-\dfrac{3}{4}\right):\left(7-\dfrac{1}{4}-\dfrac{5}{8}\right)\)
\(=\left(\dfrac{36}{4}-\dfrac{2}{4}-\dfrac{3}{4}\right):\left(\dfrac{56}{8}-\dfrac{2}{8}-\dfrac{5}{8}\right)\)
\(=\dfrac{31}{4}:\dfrac{49}{8}\)
\(=\dfrac{62}{49}\)
\(d,3-\dfrac{1-\dfrac{1}{7}}{1+\dfrac{1}{7}}=3-\dfrac{\dfrac{7}{7}-\dfrac{1}{7}}{\dfrac{7}{7}+\dfrac{1}{7}}=3-\left(\dfrac{6}{7}:\dfrac{8}{7}\right)=3-\dfrac{3}{4}=\dfrac{9}{4}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
bÀI LÀM
a) x4+x3+2x2+x+1=(x4+x3+x2)+(x2+x+1)=x2(x2+x+1)+(x2+x+1)=(x2+x+1)(x2+1)
b)a3+b3+c3-3abc=a3+3ab(a+b)+b3+c3 -(3ab(a+b)+3abc)=(a+b)3+c3-3ab(a+b+c)
=(a+b+c)((a+b)2-(a+b)c+c2)-3ab(a+b+c)=(a+b+c)(a2+2ab+b2-ac-ab+c2-3ab)=(a+b+c)(a2+b2+c2-ab-ac-bc)
c)Đặt x-y=a;y-z=b;z-x=c
a+b+c=x-y-z+z-x=o
đưa về như bài b
d)nhóm 2 hạng tử đầu lại và 2hangj tử sau lại để 2 hạng tử sau ở trong ngoặc sau đó áp dụng hằng đẳng thức dề tính sau đó dặt nhân tử chung
e)x2(y-z)+y2(z-x)+z2(x-y)=x2(y-z)-y2((y-z)+(x-y))+z2(x-y)
=x2(y-z)-y2(y-z)-y2(x-y)+z2(x-y)=(y-z)(x2-y2)-(x-y)(y2-z2)=(y-z)(x2-2y2+xy+xz+yz)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(A=\frac{1}{3}\)
\(B=\frac{25}{11}.\frac{13}{12}.\left(-2,2\right)=\frac{-65}{12}\)
\(C=\frac{11}{20}.\left(-\frac{2}{5}\right)=-\frac{11}{50}\)
tự sắp xếp nha
A= 2/3 +3/4 . -4/9
= 2/3 - 1/3
= 1/3
B=\(2\frac{3}{11}.1\frac{1}{12}.\left(-2,2\right)\)
= 25/11.13/12.-11/5
= (25/11.-11/5).13/12
= -5 . 13/12
= -65/12
C= (3/4-0,2)(0,4-4/5)
= (0,75 - 0,2)( 0,4 - 0,8)
= 0,55 . -0,4
= -0,22 = -11/50
Ta có: A= 1/3 ; B=-65/12 ; C= -11/50
=> -65/12 < -11/50 < 0
Mà 1/3 > 0 => -65/ 12 < -11/50 < 1/3
Vậy b<c<a
![](https://rs.olm.vn/images/avt/0.png?1311)
\(1,\\ a,=\left(\dfrac{1}{4}\right)^3\cdot32=\dfrac{1}{64}\cdot32=\dfrac{1}{2}\\ b,=\left(\dfrac{1}{8}\right)^3\cdot512=\dfrac{1}{512}\cdot512=1\\ c,=\dfrac{2^6\cdot2^{10}}{2^{20}}=\dfrac{1}{2^4}=\dfrac{1}{16}\\ d,=\dfrac{3^{44}\cdot3^{17}}{3^{30}\cdot3^{30}}=3\\ 2,\\ a,A=\left|x-\dfrac{3}{4}\right|\ge0\\ A_{min}=0\Leftrightarrow x=\dfrac{3}{4}\\ b,B=1,5+\left|2-x\right|\ge1,5\\ A_{min}=1,5\Leftrightarrow x=2\\ c,A=\left|2x-\dfrac{1}{3}\right|+107\ge107\\ A_{min}=107\Leftrightarrow2x=\dfrac{1}{3}\Leftrightarrow x=\dfrac{1}{6}\)
\(d,M=5\left|1-4x\right|-1\ge-1\\ M_{min}=-1\Leftrightarrow4x=1\Leftrightarrow x=\dfrac{1}{4}\\ 3,\\ a,C=-\left|x-2\right|\le0\\ C_{max}=0\Leftrightarrow x=2\\ b,D=1-\left|2x-3\right|\le1\\ D_{max}=1\Leftrightarrow x=\dfrac{3}{2}\\ c,D=-\left|x+\dfrac{5}{2}\right|\le0\\ D_{max}=0\Leftrightarrow x=-\dfrac{5}{2}\)
\(A=\dfrac{5}{4}\cdot\dfrac{15-4}{3}\cdot\dfrac{-1}{11}=\dfrac{5}{4}\cdot\dfrac{11}{3}\cdot\dfrac{-1}{11}=\dfrac{-5}{12}\)=-50/120
\(B=\dfrac{3}{4}\cdot\dfrac{-1}{12}\cdot\dfrac{-2}{3}=\dfrac{3\cdot2}{4\cdot12\cdot3}=\dfrac{2}{4\cdot12}=\dfrac{1}{24}\)=5/120
\(C=\dfrac{5}{4}\cdot\dfrac{-1}{15}\cdot\dfrac{-2}{5}=\dfrac{2}{4\cdot15}=\dfrac{1}{30}\)=4/120
\(D=3\cdot\dfrac{8-15}{12}\cdot\dfrac{-1}{7}=\dfrac{1}{4}\)=30/120
Vì -50<4<5<30
nên A<C<B<D