Tuyển Cộng tác viên Hoc24 nhiệm kì 26 tại đây: https://forms.gle/dK3zGK3LHFrgvTkJ6
\(50-\left[\left[20-2^3\right]:2+34\right]=50-\left[\left[20-8\right]:2+34\right]\)
\(=50-\left[12:2+34\right]=50-\left[6+34\right]=50-40=10\)
Tìm x :
\(a,x.\left(5x+10\right)+5.\left(x23+30\right)-9.\left(3x+5\right)=100\)
\(b,10.\left(8x+9x\right)+8.\left(2x-1\right)-2.\left(5-6x\right)=20\)
\(c,\left(x.5^2\right).\left(194+x.20\right)=50\)
Tính nhanh:\(\left(32^2-1^2\right)+\left(34^2-3^2\right)+\left(36^2-5^2\right)+...+\left(56^2-25^2\right)+\left(58^2-27^2\right)+\left(60^2-29^2\right)\)
Tính tổng :\(S=1+\frac{1}{2}.\left(1+2\right)+\frac{1}{3}.\left(1+2+3\right)+\frac{1}{4}.\left(1+2+3+4\right)+....+\frac{1}{50}.\left(1+2+3+4+....+50\right)\)
\(A=-5^{22}-\left\{-222-\left[-122-\left(100-5^{22}\right)+2022\right]\right\}\)
\(B=1+\dfrac{1}{2}\left(1+2\right)+\dfrac{1}{3}\left(1+2+3\right)+...+\dfrac{1}{20}\left(1+2+3+...+20\right)\)
\(C=\dfrac{5.4^6.9^4-3^9.\left(-8\right)^4}{4.2^{13}.3^8+2.8^4.\left(-27\right)^3}\)
B=\(1+\dfrac{1}{2}\left(1+2\right)+\dfrac{1}{3}\left(1+2+3\right)+...+\dfrac{1}{20}\left(1+2+3+...+20\right)\)
Thực hiện phép tính:
C=\(-\dfrac{1}{3}\left(1+2+3\right)-\dfrac{1}{4}\left(1+2+3+4\right)-....-\dfrac{1}{50}\left(1+2+3+...+50\right)\)
các bạn gúp mình với nha!
Bài 2 :
a, \(\frac{3}{\left(x+2\right)\left(x+5\right)}+\frac{5}{\left(x+5\right)\left(x+10\right)}+\frac{7}{\left(x+10\right)\left(x+17\right)}=\frac{x}{\left(x+2\right)\left(x+17\right)}\)
b, \(\frac{2}{\left(x-1\right)\left(x-3\right)}+\frac{5}{\left(x-3\right)\left(x-8\right)}+\frac{12}{\left(x-8\right)\left(x-20\right)}-\frac{1}{\left(x-20\right)}=\frac{-3}{4}\)
\(50-\left[\left(50-2^3.5\right):2+3\right]\)
Tính : \(S=1+\frac{1}{2}\left(1+2\right)+\frac{1}{3}\left(1+2+3\right)+\frac{1}{4}\left(1+2+3+4\right)+...+\frac{1}{20}\left(1+2+3+..+20\right)\)