tính
a. 27 . 75 + 25 . 27 - 150
b. 3.5^2 - 16 : 2^2
c. 20 - [ 30 - ( 5 -1 )^2]
d. 60 : { [(12-3) . 2] + 2}
Các bạn giúp mình với ạ. Dấu . Là dấu nhân nhé. 1. Tính
a, 27 .75 +25 .27 -150. b, 3 .5 mũ 2 -16 :2 mũ 2 c, 20 -[30 -(5 -1)mũ 2]. d, 60 :{[(12 -3). 2]+2}
a) 27 . 75 + 25 .27 - 150 = 27 . (75 + 25) - 150
= 270 . 100 - 150
= 27 000 - 150
= 26 850
b) 3.52 - 16 : 22 = 12,25 - 16 : 4
= 12,25 - 4
= 8,25
c) 20 - [30 - (5 - 1)2 ] = 20 - [30 - 42 ]
= 20 - 30 - 16
= (-10) - 16
= -26
d) 60 : {[(12 - 3) . 2] + 2} = 60 : {[9 . 2] + 2}
= 60 : {18 + 2}
= 60 : 20
= 3
Rút gọn các biểu thức sau a)√27-✓12+✓48-5✓3 b)5✓18-✓5+✓20+✓1 2 C)✓25:✓16=✓36:✓9 D)✓12+✓27-5✓3 E)2✓3-✓75+2✓12
a: \(=3\sqrt{3}-2\sqrt{3}+4\sqrt{3}-5\sqrt{3}=2\sqrt{3}\)
Bài 1.Thực hiện các phép tính sau:a)217 320 : 4;
b) 5025:5-25:5 ;
c) 218-180:2:9 ;
d)(328-8):32
Bài 2.Thực hiện phép tính.a) 27 . 75 + 25 . 27 –150
b)12 : { 400 : [500 –(125 + 25 . 7)]}
c) 13 . 17 –256 : 16 + 14 : 7 –1
d) 18 : 3 + 182 + 3.(51 : 17)
ko có bài 3 nhé!!
Bài 4.Thực hiện phép tínha) 375 : {32 –[ 4 + (5. 32–42)]} –14
b) {210 : [16 + 3.(6 + 3. 22)]} –3
Bài 1: Thực hiện các phép tính sau:
\(a)\)Chưa rỏ đề
\(b)\)\(5025\div5-25\div5\)
\(=\)\(1005-5\)
\(=\)\(1000\)
\(c)\)\(218-180\div2\div9\)
\(=\)\(218-10\)
\(=\)\(208\)
\(d)\)\(\left(328-8\right)\div32\)
\(=\)\(320\div32\)
\(=\)\(10\)
Bài 1:
a) ( Tôi không nhìn rõ đầu bài )
b) 5025 : 5 - 25 : 5
= ( 5025 - 25 ) : 5
= 5000 : 5
= 1000
c) 218 - 180 : 2 : 9
= 218 - 180 : ( 2 . 9 )
= 218 - 180 : 18
= 218 - 10
= 208
d) ( 328 - 8 ) : 32
= 320 : 32
= 10
Bài 2: Thực hiện phép tính:
\(a)\)\(27.75+25.27-150\)
\(=\)\(27.\left(75+25\right)-150\)
\(=\)\(27.100-150\)
\(=\)\(2700-150\)
\(=\)\(2550\)
\(b)\)\(12\div\left\{400\div\left[500-\left(125+25.7\right)\right]\right\}\)
\(=\)\(12\div\left\{400\div\left[500-\left(125+175\right)\right]\right\}\)
\(=\)\(12\div\left\{400\div\left[500-300\right]\right\}\)
\(=\)\(12\div\left\{400\div200\right\}\)
\(=\)\(12\div2\)
\(=\)\(6\)
\(c)\)\(13.17-256\div16+14\div7-1\)
\(=\)\(221-16+2-1\)
\(=\)\(206\)
\(d)\)\(18\div3+182+3.\left(51\div17\right)\)
\(=\)\(6+182+3.3\)
\(=\)\(6+182+9\)
\(=\)\(197\)
Bài 1:Tính
a)(-12)+25+75+12;
b)60+12+(-17)+(-43)
c)(-2)+(-87)+(-18)+87;
d)(-1)+(-2)+36+(-17)
Bài 2:Tính
a)(-17) . 6
b)8 . (-125)
c)(-12) . (-15)
d)21 . (- 3)+(- 21 ) . 7
Bài 1:
a: =25+75=100
b: =60-17-43+12=12
c: =-2-18=-20
d: =-3+36-17=36-20=16
Bài 2:
a: =-102
b: =-1000
c: =12x15=180
d: =21x(-10)=-210
B1
a 100
b 12
c -20
d 16
B2
a -102
b -1000
c 180
d -210
Bài 1:Tính
a)(-12)+25+75+12 = 100
b)60+12+(-17)+(-43)=12
c)(-2)+(-87)+(-18)+87=-20
d)(-1)+(-2)+36+(-17)=16
Bài 2:Tính
b)8 . (-125)=-100
c)(-12) . (-15)=180
d)21 . (- 3)+(- 21 ) . 7=-210
1) thực hiện phép tính
a) \(2\sqrt{\dfrac{16}{3}}-3\sqrt{\dfrac{1}{27}}-6\sqrt{\dfrac{4}{75}}\)
b) \(\left(6\sqrt{\dfrac{8}{9}}-5\sqrt{\dfrac{32}{25}}+14\sqrt{\dfrac{18}{49}}\right).\sqrt{\dfrac{1}{2}}\)
c) \(\sqrt{\left(\sqrt{2}-2\right)^2}-\sqrt{6+4\sqrt{2}}\)
giúp mk vs ạ mk đang cần gấp
a)\(2\sqrt{\dfrac{16}{3}}-3\sqrt{\dfrac{1}{27}}-6\sqrt{\dfrac{4}{75}}\)
\(=2.\sqrt{\dfrac{4^2}{3}}-3.\sqrt{\dfrac{1}{3.3^2}}-6\sqrt{\dfrac{2^2}{3.5^2}}\)
\(=2.\dfrac{4}{\sqrt{3}}-3.\dfrac{1}{3\sqrt{3}}-6.\dfrac{2}{5\sqrt{3}}=\dfrac{8}{\sqrt{3}}-\dfrac{1}{\sqrt{3}}-\dfrac{12}{5\sqrt{3}}\)\(=\dfrac{23}{5\sqrt{3}}=\dfrac{23\sqrt{3}}{15}\)
b)\(\left(6\sqrt{\dfrac{8}{9}}-5\sqrt{\dfrac{32}{25}}+14\sqrt{\dfrac{18}{49}}\right).\sqrt{\dfrac{1}{2}}\)
\(=6\sqrt{\dfrac{8}{9}.\dfrac{1}{2}}-5\sqrt{\dfrac{32}{25}.\dfrac{1}{2}}+14\sqrt{\dfrac{18}{49}.\dfrac{1}{2}}\)
\(=6\sqrt{\dfrac{4}{9}}-5\sqrt{\dfrac{16}{25}}+14\sqrt{\dfrac{9}{49}}\)\(=6.\dfrac{2}{3}-5.\dfrac{4}{5}+14.\dfrac{3}{7}=6\)
c)\(\sqrt{\left(\sqrt{2}-2\right)^2}-\sqrt{6+4\sqrt{2}}=\left|\sqrt{2}-2\right|-\sqrt{4+2.2\sqrt{2}+2}=2-\sqrt{2}-\sqrt{\left(2+\sqrt{2}\right)^2}\)
\(=2-\sqrt{2}-\left(2+\sqrt{2}\right)=-2\sqrt{2}\)
bài 2: rút gọn rồi tính
a) 8/5 -18/27 =.................................................. .................................................. b)12/20-6/18............................................ c)18/21-12/27...................................... d)8/12-20/50................................................. |
|
a: =8/5-2/3=24/15-10/15=14/15
12/20-6/18=3/5-1/3=9/15-5/15=4/15
b: 18/21-12/27=6/7-7/9=54/63-49/63=5/63
8/12-20/50=2/3-2/5=10/15-6/15=4/15
\(a,\dfrac{8}{5}-\dfrac{18}{27}=\dfrac{8}{5}-\dfrac{2}{3}=\dfrac{14}{15}\\ \dfrac{12}{20}-\dfrac{6}{18}=\dfrac{3}{5}-\dfrac{1}{3}=\dfrac{4}{15}\\ b,\dfrac{18}{21}-\dfrac{12}{27}=\dfrac{6}{7}-\dfrac{4}{9}=\dfrac{26}{63}\\ \dfrac{8}{12}-\dfrac{20}{50}=\dfrac{2}{3}-\dfrac{2}{5}=\dfrac{4}{15}\)
a) 8/5 -18/27 = 8/5 - 2/3 = 14/15 12/20 - 6/18 = 3/5 - 1/3 = 4/15 b) 18/21 - 12/27 = 6/7 - 4/9 = 26/63 8/12 - 20/50 = 2/3 - 2/5 = 4/15 |
Tìm x biết
d) 32%-0,25:x=-17/5
e)(x+1/5)^2+17/25=26/25
f)-32/27-(3x-7/9)^3=-24/27
g)60%x+0,4x+x:3=2
h)|20/9-x|=1/12+1/20+1/30+1/42+1/56+1/72
i)8/5+(2/7+2/17+2/37/5/7+5/17+5/37).x=16/5
Lưu ý: câu i 2/7+2/17+2/37 phần(vế trên) 5/7+5/17+5/37(vế dưới)
d) Ta có: \(32\%-0.25:x=-\dfrac{17}{5}\)
\(\Leftrightarrow0.25:x=\dfrac{8}{25}+\dfrac{17}{5}=\dfrac{93}{25}\)
hay \(x=\dfrac{25}{372}\)
Vậy: \(x=\dfrac{25}{372}\)
e) Ta có: \(\left(x+\dfrac{1}{5}\right)^2+\dfrac{17}{25}=\dfrac{26}{25}\)
\(\Leftrightarrow\left(x+\dfrac{1}{5}\right)^2=\dfrac{9}{25}\)
\(\Leftrightarrow\left[{}\begin{matrix}x+\dfrac{1}{5}=\dfrac{3}{5}\\x+\dfrac{1}{5}=-\dfrac{3}{5}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{2}{5}\\x=-\dfrac{4}{5}\end{matrix}\right.\)
Vậy: \(x\in\left\{\dfrac{2}{5};-\dfrac{4}{5}\right\}\)
f) Ta có: \(-\dfrac{32}{27}-\left(3x-\dfrac{7}{9}\right)^3=-\dfrac{24}{27}\)
\(\Leftrightarrow\left(3x-\dfrac{7}{9}\right)^3=\dfrac{-8}{27}\)
\(\Leftrightarrow3x-\dfrac{7}{9}=-\dfrac{2}{3}\)
\(\Leftrightarrow3x=\dfrac{1}{9}\)
hay \(x=\dfrac{1}{27}\)
g) Ta có: \(60\%\cdot x+0.4x+x:3=2\)
\(\Leftrightarrow\dfrac{4}{3}x=2\)
hay \(x=\dfrac{3}{2}\)
Vậy: \(x=\dfrac{3}{2}\)
h) PT \(\Leftrightarrow\left|\dfrac{20}{9}-x\right|=\dfrac{2}{9}\) \(\Rightarrow\left[{}\begin{matrix}\dfrac{20}{9}-x=\dfrac{2}{9}\\x-\dfrac{20}{9}=\dfrac{2}{9}\end{matrix}\right.\) \(\Leftrightarrow\left[{}\begin{matrix}x=2\\x=\dfrac{22}{9}\end{matrix}\right.\)
Vậy ...
i) PT \(\Leftrightarrow\dfrac{8}{5}+\dfrac{2}{5}x=\dfrac{16}{5}\) \(\Leftrightarrow\dfrac{2}{5}x=\dfrac{8}{5}\) \(\Leftrightarrow x=4\)
Vậy ...
1 . tính :
27 . 75 + 25 . 27 - 150
20 - [ 30 - ( 5 - 1 )2 ]
27 . 75 + 25 . 27 - 150
= 27.(75+25)-150
= 27.100-150
= 2700 - 150
= 2550
20 - [ 30 - ( 5 - 1 )2 ]
= 20 -[30-42 ]
= 20 - ( 14 )
= 6
27 . 75 + 25 . 27 - 150
= 27.(75+25)-150
= 27.100-150
= 2700 - 150
= 2550
20 - [ 30 - ( 5 - 1 )2 ]
= 20 -[30-42 ]
= 20 - ( 14 )
= 6