Tính nhanh giá trị biểu thức sau: \(\frac{43^3+17^3}{43^3+26^3}\)
Tính nhanh giá trị biểu thức:
(43^3 + 17^3) : (43^3 + 26^3)
Tính nhanh giá trị mỗi biểu thức sau :
A= 18/26+-5/27+-22/86+12/39+-32/43
B= -10/12+8/15+-19/56+3/-18+28/60
A = \(\dfrac{18}{26}\) + (-\(\dfrac{5}{27}\)) + (-\(\dfrac{22}{86}\)) + \(\dfrac{12}{39}\) - \(\dfrac{32}{43}\)
A = \(\dfrac{9}{13}\) - \(\dfrac{5}{27}\) - \(\dfrac{11}{43}\) + \(\dfrac{4}{13}\) - \(\dfrac{32}{43}\)
A = (\(\dfrac{9}{13}\) + \(\dfrac{4}{13}\)) - (\(\dfrac{11}{43}\) + \(\dfrac{32}{43}\)) - \(\dfrac{5}{27}\)
A = \(\dfrac{13}{13}\) - \(\dfrac{43}{43}\) - \(\dfrac{5}{27}\)
A = 1 - 1 - \(\dfrac{5}{27}\)
A = 0 - \(\dfrac{5}{27}\)
A = - \(\dfrac{5}{27}\)
B = -\(\dfrac{10}{12}\) + \(\dfrac{8}{15}\) - \(\dfrac{19}{56}\) + \(\dfrac{3}{-18}\) + \(\dfrac{28}{60}\)
B = - \(\dfrac{5}{6}\) + \(\dfrac{8}{15}\) - \(\dfrac{19}{56}\) - \(\dfrac{1}{6}\) + \(\dfrac{7}{15}\)
B = -(\(\dfrac{5}{6}\) + \(\dfrac{1}{6}\)) - \(\dfrac{19}{56}\) + (\(\dfrac{8}{15}\) + \(\dfrac{7}{15}\))
B = -1 - \(\dfrac{19}{56}\) + 1
B = - \(\dfrac{19}{56}\)
CMR : \(\frac{43^3+17^3}{43^3+26^3}=\frac{43+17}{43+26}\)
\(\frac{43^3+17^3}{43^3+26^3}=\frac{\left(43+17\right)\left(43^2-43×17+17^2\right)}{\left(43+26\right)\left(43^2-43×26+26^2\right)}=\frac{\left(43+17\right)×1407}{\left(43+26\right)×1407}=\frac{43+17}{43+26}\left(dpcm\right)\)
1. Tính nhanh giá trị mỗi biểu thức sau:
A = 18/26 + -5/27 + -22/86 + 12/39 +-32/43
B =-10/12 + 8/15 + -19/56 + 3/-18 + 28/60.
Tính nhanh giá trị các biểu thức sau:
a) 3.4.25.8.125 b) 36.63+ 64.63
c) 45.129+ 71.45 d) 26. (43+ 57)+ 74(57 +43)
a) \(3\cdot4\cdot25\cdot8\cdot125\)
\(=\left(125\cdot8\right)\cdot\left(4\cdot25\right)\cdot3\)
\(=1000\cdot100\cdot3\)
\(=300000\)
b) \(36\cdot63+64\cdot663\)
\(=63\cdot\left(36+64\right)\)
\(=63\cdot100\)
\(=6300\)
c) \(45\cdot129+71\cdot129\)
\(=129\cdot\left(129+71\right)\)
\(=129\cdot200\)
\(=25800\)
d) \(26\cdot\left(43+57\right)+74\cdot\left(43+57\right)\)
\(=26\cdot100+74\cdot100\)
\(=2600+7400\)
\(=10100\)
a) 3.4.25.8.125
=3(4.25).(8.125)
=3.100.1000
300000
b) 36.63+ 64.63
=(36+64).63
=100.63
=6300
c) 45.129+ 71.45
=45.(129+71)
=45.200
=9000
d) 26. (43+ 57)+ 74(57 +43)
=26.43+26.57 + 74.57 + 74.43
=(26.43+74.43)+(26.57 + 74.57 )
= [43.(26+74)]+[ (26+74).57]
=[43.100]+[100.57]
=4300+5700
= 10000
Tính nhanh giá trị mỗi biểu thức sau
A =18 phần 26 + -5 phần 27 + -22 phần 86 + 12 phần 39 + -32 phần 43
B = -10 phần 12 + 8 phần 15 + -19 phần 56 + 3 phần -18 + 28 phần 60
A = 18/26 + -5/27 + -22/86 + 12/39 + -32/43
A = 9/13 + -5/27 + -11/43 + 4/13 + -32/43
A = -5/27 + ( 9/13 + 4/13 ) + ( -11/43 + -32/43 )
A = -5/27 + 1 + ( -1)
A = -5/27 + 0
A = 0
B = -10/12 + 8/15 + -19/56 + 3/-18 + 28/60
B = -5/6 + 8/15 + -19/56 + -1/6 + 7/15
B = -19/56 + ( -5/6 + -1/6 ) + ( 8/15 + 7/15 )
B = -19/56 + ( -1 ) + 1
B = -19/56 + 0
B = 0
Thông cảm ...Vì không biết sử dụng phân số nên đành viết bằng dấu gạch chéo
CMR: (43^3+17^3)/(43^3+26^3)=(43+17)/(43+26)
\(VT=\frac{\left(43+17\right)\left(43^2-43.17+17^2\right)}{\left(43+26\right)\left(43^2-43.26+26^2\right)}=\frac{\left(43+17\right)\left[43^2-17\left(43-17\right)\right]}{\left(43+26\right)\left[43^2-26\left(43-26\right)\right]}.\)
\(VT=\frac{\left(43+17\right)\left(43^2-17.26\right)}{\left(43+26\right)\left(43^2-26.17\right)}=\frac{43+17}{43+26}=VP\left(dpcm\right)\)
Bỏ ngoặc rồi tính nhanh giá trị biểu thức sau:
A = [ -(-43) + 20 ] - [ -(-43) - (-20) ]