1. Thực hiện phép tính
a) \(25-\left(-75\right)+32-\left(32+75\right)\)
b) \(\left|-127\right|-18.\left(5-6\right)\)
c) \(17-25+55-17\)
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)\(\sqrt{\left(\sqrt{2}-2\right)^2}-\sqrt{6+4\sqrt{2}}=\left|\sqrt{2}-2\right|-\sqrt{4+2.2\sqrt{2}+2}=2-\sqrt{2}-\sqrt{\left(2+\sqrt{2}\right)^2}\)
\(=2-\sqrt{2}-\left(2+\sqrt{2}\right)=-2\sqrt{2}\)
Bỏ dấu ngoặc rồi tính:
a) \(\left( {4 + 32 + 6} \right) + \left( {10 - 36 - 6} \right)\)
b) \(\left( {77 + 22 - 65} \right) - \left( {67 + 12 - 75} \right)\)
c) \( - \left( { - 21 + 43 + 7} \right) - \left( {11 - 53 - 17} \right)\)
a)
Cách 1.
\(\begin{array}{l}\left( {4 + 32 + 6} \right) + \left( {10 - 36 - 6} \right)\\ = 4 + 32 + 6 + 10 - 36 - 6\\ = 52 + \left( { - 36} \right) + \left( { - 6} \right)\\ = 52 + \left( { - 42} \right) = 52 - 42 = 10\end{array}\)
Cách 2.
\(\begin{array}{l}\left( {4 + 32 + 6} \right) + \left( {10 - 36 - 6} \right)\\ = 4 + 32 + 6 + 10 - 36 - 6\\ = 36 + 6 + 10 + \left( { - 36} \right) + \left( { - 6} \right)\\ = 36 + \left( { - 36} \right) + 6 + \left( { - 6} \right) + 10\\ = 0 + 0 + 10 = 10\end{array}\)
b) \(\left( {77 + 22 - 65} \right) - \left( {67 + 12 - 75} \right)\)
\(\begin{array}{l} = 77 + 22 - 65 - 67 - 12 + 75\\ = 77 - 67 + 22 - 12 + 75 - 65\\ = 10 + 10 + 10 = 30\end{array}\)
c) \( - \left( { - 21 + 43 + 7} \right) - \left( {11 - 53 - 17} \right)\)
\(\begin{array}{l} = 21 - 43 - 7 - 11 + 53 + 17\\ = 21 - 11 + 53 - 43 + 17 - 7\\ = 10 + 10 + 10 = 30\end{array}\)
bài 3 thực hiện phép tính
a\(\dfrac{5}{8}+\dfrac{3}{17}+\dfrac{4}{18}+\dfrac{20}{-17}+\dfrac{-2}{9}+\dfrac{21}{56}\)
b\(\left(\dfrac{9}{16}+\dfrac{8}{-27}\right)+\left(1+\dfrac{7}{16}+\dfrac{-19}{27}\right)\)
c\(\left(\dfrac{13}{5}+\dfrac{7}{16}\right)+\left(\dfrac{-15}{16}+\dfrac{6}{15}\right)\) d \(\left(6-2\dfrac{4}{5}\right).3\dfrac{1}{8}-1\dfrac{3}{5}:\dfrac{1}{4}\)
a) Ta có: \(\dfrac{5}{8}+\dfrac{3}{17}+\dfrac{4}{18}+\dfrac{20}{-17}+\dfrac{-2}{9}+\dfrac{21}{56}\)
\(=\left(\dfrac{3}{17}-\dfrac{20}{17}\right)+\left(\dfrac{2}{9}-\dfrac{2}{9}\right)+\left(\dfrac{5}{8}+\dfrac{3}{8}\right)\)
\(=-1+1=0\)
b) Ta có: \(\left(\dfrac{9}{16}+\dfrac{8}{-27}\right)+\left(1+\dfrac{7}{16}+\dfrac{-19}{27}\right)\)
\(=\left(\dfrac{9}{16}+\dfrac{7}{16}\right)+\left(\dfrac{-8}{27}-\dfrac{19}{27}\right)+1\)
=1-1+1=1
Bài 1:
1/\(\left(-\dfrac{25}{13}\right)+\left(-\dfrac{19}{17}\right)+\dfrac{12}{13}+\left(-\dfrac{25}{17}\right)\) 6/ \(2\dfrac{2}{15}.\dfrac{9}{17}.\dfrac{3}{32}:\left(-\dfrac{3}{17}\right)\)
2/\(\dfrac{1}{2}-\left(-\dfrac{1}{3}\right)+\dfrac{1}{23}+\dfrac{1}{6}\) 7/\(\left(\dfrac{-3}{4}+\dfrac{2}{5}\right):\dfrac{3}{7}+\left(\dfrac{3}{5}+\dfrac{-1}{4}\right):\dfrac{3}{7}\)
3/\(\left(-\dfrac{3}{7}\right).\dfrac{5}{11}+\left(-\dfrac{5}{14}\right).\dfrac{5}{11}\) 8/\(\left(-\dfrac{1}{3}\right).\left(-\dfrac{15}{19}\right).\dfrac{38}{45}\)
4/\(\left(-\dfrac{5}{11}\right).\dfrac{7}{15}.\dfrac{11}{-5}.\left(-30\right)\) 9/\(\dfrac{1}{2.3}+\dfrac{1}{3.4}+\dfrac{1}{4.5}+......+\dfrac{1}{19.20}\)
5/\(\left(-\dfrac{5}{9}\right).\dfrac{3}{11}+\left(-\dfrac{13}{18}\right).\dfrac{3}{11}\) 10/\(\dfrac{1}{9.10}-\dfrac{1}{8.9}-\dfrac{1}{7.8}-......-\dfrac{1}{2.3}-\dfrac{1}{1.2}\)
Thực hiện phép tính
a)17 – 25 + 55 – 17
b) 25 - (-75) + 32 - (32+75)
c) (-5).8.(-2).3
d) (-15) + (- 122)
e) - 18.( 5 - 6)
a) 17 - 25 + 55 - 17 = (17 - 17) + (55-25)= 0 + 20 = 30
b) 25 - (-75) + 32 - (32 + 75) = 25 + 75 +32 - 32 - 75 = 25 + (75-75)+(32-32) = 25
c) (-5).8.(-2).3= 10.24=240
d) (-15)+(-122)= -137
e) -18.(5 - 6) = -18 .(-1)= 18.
BYE :3
1) (-6 - 2) . (-6 + 2)
2) 627 + 125 + (-627) + |-46| -21
3) (-25) + 30 + (-16) + 25 + (-4)
4) 75 - 5.(15 - 40) - (-60)
5) |31 - 17| - |15 - 52|
6) 13 - 18 - (-42) - 15
7) 369.4.[(- 5) + 4. (-8) ]
8) \(\left(-8\right)^3\) : \(\left(-8\right)^2\) + 8
9) 72 : (-6 . 2 + 4)
1) (-6 - 2) . (-6 + 2) = -8 . (-4) = 32
2) 627 + 125 + (-627) + |-46| -21 = 125 + 46 - 21 = 150
3) (-25) + 30 + (-16) + 25 + (-4) = 30 + (-20) = 10
4) 75 - 5.(15 - 40) - (-60) = 75 - 75 + 80 + 60 = 140
5) |31 - 17| - |15 - 52| = |14| - |-37| = 14 - 37 = -23
6) 13 - 18 - (-42) - 15 = 13 - 18 + 42 - 15 = 22
3 bài sau hết kiên nhẫn rồi, thông cảm nhé.
7) 369.4.[(- 5) + 4. (-8) ]
= 1476 . [(-5) + (-32)]
= 1476 . -37
= -54612
8) (−8)3 : (−8)2 + 8
= 8 + 8
= 16
9) 72 : (-6 . 2 + 4)
= 72 : (-12 + 4)
= 72 : (-8)
= -9
thực hiện phép tính
a)\(\dfrac{3}{5}\)-\(\dfrac{1}{2}\)\(\sqrt{1\dfrac{11}{25}}\)
b)(5+2\(\sqrt{6}\))(5-2\(\sqrt{6}\))
c)\(\sqrt{\left(2-\sqrt{3}\right)^2}\)+\(\sqrt{4-2\sqrt{3}}\)
d)\(\dfrac{\left(x\sqrt{y}+y\sqrt{x}\right)\left(\sqrt{x}-\sqrt{y}\right)}{\sqrt{xy}}\)(với x,y>0)
\(a,\dfrac{3}{5}-\dfrac{1}{2}\sqrt{1\dfrac{11}{25}}=\dfrac{3}{5}-\dfrac{1}{2}\sqrt{\dfrac{36}{25}}=\dfrac{3}{5}-\dfrac{1}{2}.\dfrac{\sqrt{6^2}}{\sqrt{5^2}}=\dfrac{3}{5}-\dfrac{1}{2}.\dfrac{6}{5}=\dfrac{3}{5}-\dfrac{6}{10}=\dfrac{3}{5}-\dfrac{3}{5}=0\)
\(b,\left(5+2\sqrt{6}\right)\left(5-2\sqrt{6}\right)=5^2-\left(2\sqrt{6}\right)^2=25-2^2.\sqrt{6^2}=25-4.6=25-24=1\)
\(c,\sqrt{\left(2-\sqrt{3}\right)^2}+\sqrt{4-2\sqrt{3}}\\ =\left|2-\sqrt{3}\right|+\sqrt{\sqrt{3^2}-2\sqrt{3}+1}\\ =2-\sqrt{3}+\sqrt{\left(\sqrt{3}-1\right)^2}\\ =2-\sqrt{3}+\left|\sqrt{3}-1\right|\\ =2-\sqrt{3}+\sqrt{3}-1\\ =1\)
\(d,\dfrac{\left(x\sqrt{y}+y\sqrt{x}\right)\left(\sqrt{x}-\sqrt{y}\right)}{\sqrt{xy}}\left(dk:x,y>0\right)\\ =\dfrac{\left(\sqrt{x^2}.\sqrt{y}+\sqrt{y^2}.\sqrt{x}\right)\left(\sqrt{x}-\sqrt{y}\right)}{\sqrt{xy}}\\ =\dfrac{\sqrt{xy}\left(\sqrt{x}+\sqrt{y}\right)\left(\sqrt{x}-\sqrt{y}\right)}{\sqrt{xy}}\\ =\sqrt{x^2}-\sqrt{y^2}\\ =\left|x\right|-\left|y\right|\\ =x-y\)
Bài1: Thực hiện phép tính
a) 17-25+55-17 b) 25-(-75)+32-(32+75) c) (-5).8.(-2).3
d) (-15)+(-122) e) (7-10)+3 f) |-127|-18.(5.6)
\(17-25+55-17\)
\(=(17-17)+(55-25)\)
\(=0+30=30\)
\(25-(-75)+32-(32+75)\)
\(=25+75+32-32-75\)
\(=(32-32)+(75-75)+25=25\)
\((-5).8.(-2).3\)
\(=[(-5).(-2)].(8.3)\)
\(=10.24=240\)
\((-15)+(-122)=-(15+122)=-137\)
\((7-10)+3=7-10+3\)
\(=(7+3)-10=0\)
\(|-127|-18.(5.6)\)
\(=127-18.30\)
\(=127-540=-413\)
6) Thực hiện các phép tính
a. \(\sqrt{2}\left(\sqrt{8}+\sqrt{32}-\sqrt{98}\right)\)
b. \(\dfrac{2}{\sqrt{5}+2}+\dfrac{2}{2-\sqrt{5}}\)
c. \(\left(2+\sqrt{3}\right)\sqrt{11-6\sqrt{2}}\)
Mng giúp mik vs ạ >.<!!
b, \(\dfrac{2}{\sqrt{5}+2}+\dfrac{2}{2-\sqrt{5}}\)
\(=\dfrac{2\left(\sqrt{5}-2\right)}{5-4}-\dfrac{2\left(\sqrt{5}+2\right)}{5-4}\)
\(=2\sqrt{5}-4-2\sqrt{5}-4=-8\)
a, \(\sqrt{2}\left(\sqrt{8}+\sqrt{32}-\sqrt{98}\right)\)
\(=\sqrt{2}\left(2\sqrt{2}+4\sqrt{2}-7\sqrt{2}\right)\)
\(=\sqrt{2}.\left(-\sqrt{2}\right)=-2\)
c, \(\left(2+\sqrt{3}\right)\sqrt{11-6\sqrt{2}}\)
\(=\left(2+\sqrt{3}\right)\sqrt{\left(\sqrt{2}-3\right)^2}\)
\(=\left(2+\sqrt{3}\right)\left(3-\sqrt{2}\right)\)
\(=6-2\sqrt{2}+3\sqrt{3}-\sqrt{6}\)