1:tính nhanh
A=-3^17[2^3+3^17]
B=3^17+-5^13+-18^35+14^17+17^-35
tính nhanh: A=2/7 + -3/ 8 + 11/7 + 1/ 3 + 1/ 7 + 5 / -8; B=3/17 + -5/ 13 + -18/35 + 14/ 17 + 17
\(A=\frac{2}{7}+\frac{-3}{8}+\frac{11}{7}+\frac{1}{3}+\frac{1}{7}+\frac{5}{-8}\)
\(A=\left(\frac{2}{7}+\frac{11}{7}+\frac{1}{7}\right)+\left(\frac{-3}{8}+\frac{5}{-8}\right)+\frac{1}{3}\)
\(A=2-1+\frac{1}{3}\)
\(A=\frac{4}{3}\)
\(B=\frac{3}{17}+\frac{-5}{13}+\frac{-18}{35}+\frac{14}{17}+17\)
\(B=\left(\frac{3}{17}+\frac{14}{17}\right)+\frac{-5}{13}+\frac{-18}{35}+17\)
\(B=1+\frac{-5}{13}+\frac{-18}{35}+17\)
\(B=18+\frac{-5}{13}+\frac{-18}{35}\)
\(B=\frac{7781}{455}\)
tính
3/17 + -5/13 + -18/35 + 14/17 + 17/-35 + -8/13
\(\frac{3}{17}+\frac{-5}{13}+\frac{-18}{35}+\frac{14}{17}+\frac{17}{-35}+\frac{-8}{13}\)
\(=\frac{3}{17}+\frac{-5}{13}+\frac{-18}{35}+\frac{14}{17}+\frac{-17}{35}+\frac{-8}{13}\)
\(=\left(\frac{3}{17}+\frac{14}{17}\right)+\left(\frac{-5}{13}+\frac{-8}{13}\right)+\left(\frac{-18}{35}+\frac{-17}{35}\right)\)
\(=\frac{17}{17}+\frac{-13}{13}+\frac{-35}{35}\)
\(=1+\left(-1\right)+\left(-1\right)\)
\(=-1\)
\(\frac{3}{17}+\frac{-5}{13}+\frac{-18}{35}+\frac{14}{17}+\frac{17}{-35}+\frac{-8}{13}\)
= \(\frac{3}{17}+\frac{-5}{13}+\frac{-18}{35}+\frac{14}{17}+\frac{-17}{35}+\frac{-8}{13}\)
= \(\left(\frac{3}{17}+\frac{14}{17}\right)+\left(\frac{-5}{13}+\frac{-8}{13}\right)+\frac{-18}{35}\)
= 1+(-1)+\(\frac{-18}{35}\)
= 0+\(\frac{-18}{35}\)
= \(\frac{-18}{35}\)
\(\frac{3}{17}-\frac{5}{13}-\frac{18}{35}+\frac{14}{17}-\frac{17}{35}-\frac{8}{13}=\left(\frac{3}{17}+\frac{14}{17}\right)-\left(\frac{5}{13}+\frac{8}{13}\right)-\left(\frac{18}{35}+\frac{17}{35}\right)\)
\(=1-1-1\)
=-1
Tính nhanh :
3/17 - 5/13 - 18/35 + 14/17 + 17/-35 - 8/13
3/17 - 5/13 - 18/35 + 14/17 + 17/-35 - 8/13
=(3/17+14/17)+(-5/13-8/13)+(-18/35+17/35)
=1+(-1)+(-1/35)
=-1/35
Chúc bn học tốt
\(\frac{3}{17}-\frac{5}{13}-\frac{18}{35}+\frac{14}{17}\)\(+\frac{17}{-35}-\frac{8}{13}\)
\(=\left(\frac{3}{17}+\frac{14}{17}\right)\)\(-\left(\frac{18}{35}-\frac{-17}{35}\right)\)\(-\left(\frac{5}{13}+\frac{8}{13}\right)\)
\(=1-1-1\)\(=0\)
a: =35/17-18/17-9/5+4/5
=1-1=0
b: =-7/19(3/17+8/11-1)
=7/19*18/187=126/3553
c: =26/15-11/15-17/3-6/13
=1-6/13-17/3
=7/13-17/3=-200/39
Bài 1 Tìm x biết
x= 3/4 cộng 1/-12
x/14 = 1/7 cộng -3/14
Bài 2 Tính một cách hợp lí
A= 2/7 cộng -3/8 cộng 11/7 cộng 1/3 cộng 1/7 cộng 5/-8
B= 3/17 cộng -5/13 cộng -18/35 cộng 14/17 cộng 17/-35 cộng -8/13
a,9/4-[-11}/-4
b, 7/8-3/-8-1/8
c,-5/21-25/21-[-1]/21
d, 18/24-35/-10
e, 3/7-11/14-19/28
g, 5/-{-2}/3-1/12
h, 3/17-{-5}/13-{-18}/35-14/17-17/{-35}-{-8}/13
a; \(\dfrac{9}{4}\) - \(\dfrac{-11}{4}\)
= \(\dfrac{9}{4}\) + \(\dfrac{11}{4}\)
= \(\dfrac{20}{4}\)
= 5
b; \(\dfrac{7}{8}\) - \(\dfrac{3}{-8}\) - \(\dfrac{1}{8}\)
= \(\dfrac{7}{8}\) + \(\dfrac{3}{8}\) - \(\dfrac{1}{8}\)
= \(\dfrac{7+3-1}{8}\)
= \(\dfrac{9}{8}\)
c; \(\dfrac{-5}{21}\) - \(\dfrac{25}{21}\) - \(\dfrac{-1}{21}\)
= \(\dfrac{-5}{21}\) - \(\dfrac{25}{21}\) + \(\dfrac{1}{21}\)
= \(\dfrac{-5-25+1}{21}\)
= \(\dfrac{-29}{21}\)
Tính hợp lý:
\(a.\dfrac{3}{17}+\dfrac{-5}{13}+\dfrac{-18}{35}+\dfrac{14}{17}+\dfrac{17}{-35}+\dfrac{-8}{13}\)
\(b.\dfrac{-3}{8}\cdot\dfrac{1}{6}+\dfrac{3}{-8}\cdot\dfrac{5}{6}+\dfrac{-10}{16}\)
\(c.\dfrac{-4}{11}\cdot\dfrac{5}{15}\cdot\dfrac{11}{-4}\)
a: \(=\left(\dfrac{3}{17}+\dfrac{14}{17}\right)+\left(\dfrac{-5}{13}-\dfrac{8}{13}\right)+\left(\dfrac{-18}{35}-\dfrac{17}{35}\right)\)
=1-1-1
=-1
b: \(=\dfrac{-3}{8}\left(\dfrac{1}{6}+\dfrac{5}{6}\right)+\dfrac{-5}{8}=\dfrac{-3}{8}-\dfrac{5}{8}=-1\)
c: \(=\dfrac{4}{4}\cdot\dfrac{5}{15}\cdot\dfrac{11}{11}=\dfrac{1}{3}\)
a) \(=\left(\dfrac{3}{17}+\dfrac{14}{17}\right)+\left(-\dfrac{5}{13}+-\dfrac{8}{13}\right)+\left(-\dfrac{18}{35}+-\dfrac{17}{35}\right)=1+-1+-1=-1\)
b) \(=-\dfrac{3}{8}\cdot\left(\dfrac{1}{6}+\dfrac{5}{6}\right)-\dfrac{10}{16}=-\dfrac{3}{8}-\dfrac{10}{16}=-1\)
c) \(=\left(-\dfrac{4}{11}\cdot-\dfrac{11}{4}\right)\cdot\dfrac{5}{15}=1\cdot\dfrac{1}{3}=\dfrac{1}{3}\)
a)\(=\left(-\dfrac{5}{13}+\dfrac{-8}{13}\right)+\left(-\dfrac{18}{35}-\dfrac{17}{35}\right)+\left(\dfrac{3}{14}+\dfrac{14}{17}\right)=-1-1+1=-1\)
b)\(=\dfrac{-3}{8}.\left(\dfrac{1}{6}+\dfrac{5}{6}\right)-\dfrac{10}{16}=-\dfrac{3}{8}.1-\dfrac{10}{16}=-\dfrac{6}{16}-\dfrac{10}{16}=-\dfrac{16}{16}=-1\)
c)\(\dfrac{-4.5.11}{11.5.3.-4}=\dfrac{1}{3}\)
a,-8/3+7/5+-71/15<x<-13/7+19/14+-7/2
b,-19/6+-15/2+11/3<x<-5/4+19/12+-10/3
c,-6/7+3/35<x<-2/5+3/7
d,x=3/4+1/-12
e,x/14=1/7+-3/14
f,11/18+13/6=85/x
g,8/17+5/17<x/17<6/17+9/17
Thực hiện phép tính: -1/8 + -5/3 -6/35× -49/54 6/5 - -4/3 31/17+ -5/13 +-8/13 -14/17
a: =-3/24-40/24
=-43/24
b: \(=\dfrac{6}{54}\cdot\dfrac{49}{35}=\dfrac{1}{9}\cdot\dfrac{7}{5}=\dfrac{7}{45}\)
c: \(=\dfrac{6}{5}+\dfrac{4}{3}=\dfrac{18+20}{15}=\dfrac{38}{15}\)
d: \(=\dfrac{31}{17}-\dfrac{14}{17}-\dfrac{5}{13}-\dfrac{8}{13}=1-1=0\)