tính nhanh:
\(\left(150+32\right)\cdot32+\left(250-68\right)\cdot68\)
Tìm x biết: \(\left(\frac{1}{2\cdot5}+\frac{1}{5\cdot8}+\frac{1}{8\cdot11}+...+\frac{1}{65\cdot68}\right)x-\frac{7}{34}=\frac{19}{68}\)
\(\left(\frac{3}{2.5}+\frac{3}{5.8}+...+\frac{3}{65.68}\right)x=\frac{19}{68}+\frac{7}{34}\)
\(\left(\frac{1}{2}-\frac{1}{5}+\frac{1}{5}-\frac{1}{8}+...-\frac{1}{68}\right)x=\frac{33}{68}\)
\(\left(\frac{1}{2}-\frac{1}{68}\right)x=\frac{33}{68}\)
\(\frac{33}{68}x=\frac{33}{68}\)
\(x=\frac{33}{68}:\frac{33}{68}=1\)
Tìm x biết :\(\left(\frac{1}{2\cdot5}+\frac{1}{5\cdot8}+\frac{1}{8\cdot11}+...+\frac{1}{65\cdot68}\right)x-\frac{7}{34}=\frac{19}{68}\)
Tìm x biết: \(\left(\frac{1}{2\cdot5}+\frac{1}{5\cdot8}+\frac{1}{8\cdot11}+...+\frac{1}{65\cdot68}\right)x-\frac{7}{34}=\frac{19}{68}\)
(1/2.5+1/5.8+......+1/65.68)x=19/68+7/34=33/68
(1/2.5+1/5.8+.......+1/65.68).x.3=33/68.3=99/68
(3/2.5+3/5.8=.......+3/65.68).x=99/68
(1/2-1/5+1/5-1/8+....-+1/65-1/68).x=99/68
(1/2-1/68).x=99/68
33/68.x=99/68
=>x=3
k cho mình nha
Tính nhanh:\(\left(32^2-1^2\right)+\left(34^2-3^2\right)+\left(36^2-5^2\right)+...+\left(56^2-25^2\right)+\left(58^2-27^2\right)+\left(60^2-29^2\right)\)
Bạn dựa vào công thức
a2 - n2 = (a + n)(a - n)
Bài 1 : Tính : \(100:\left\{250:\left[450-\left(4.5^2-2^2.25\right)\right]\right\}\)
=100;(250;[450-(22.52-22.52)])
=100;(250;450)=100;(5/9)=180
nhớ **** nha
\(\frac{-150.\left(1352-41\right)}{\left(1352-41\right).\left(150-15\right)}< x< \frac{\left(2400:48\right)-250}{350-\left(3600:12\right)}\)
150+32 nhân 3,2] + [250- 68] nhân 68
tính nhanh
Tính nhanh \(\left(-\frac{4}{13}+\frac{17}{19}\right):-\frac{31}{32}+\left(-\frac{9}{13}+\frac{2}{19}\right):-\frac{33}{31}\)=?
Tính nhanh \(4\cdot\left(3^2+1\right)\left(3^8+1\right)\left(3^{16}+1\right)\left(3^{32}+1\right)\left(3^{64}+1\right)\)