Question

bài 1;tính nhanh giá trị cc biểu thức sau:

a)\(A=\frac{-3}{17}+\left(\frac{2}{3}+\frac{3}{17}\right)\))

b,\(B=\frac{-5}{21}+\left(\frac{2}{3}+1\right)\)

c,\(C=\left(\frac{-1}{6}+\frac{5}{-12}\right)+\frac{7}{12}\)

Các bn ơi giúp mk với cần gấp

Answer 1

trả lời nhanh cái xem nào 

Answer 2

ko trả lời thì làm sao giỏi tự giải đi

Answer 3

\(\frac{-3+3}{17}+\frac{2}{3}=\frac{2}{3}.\)

\(\frac{-5+21}{21}+\frac{2}{3}=\frac{16}{21}+\frac{2}{3}=\frac{16+14}{21}=\frac{30}{21}\)

c,  \(\frac{-1}{6}+\frac{5}{-12}+\frac{7}{12}=\frac{2+5}{-12}+\frac{7}{12}=\frac{7}{-12}+\frac{7}{12}=\frac{7-7}{-12}\) ( câu này nhân cả tử cả mẫu cho trừ 1 nhé tự hiểu )

Answer 4

a) \(A=\frac{-3}{17}+\left(\frac{2}{3}+\frac{3}{17}\right)\)

\(=\left(\frac{-3}{17}+\frac{3}{17}\right)+\frac{2}{3}\)

\(=0+\frac{2}{3}\)

\(=\frac{2}{3}\)

Answer 5

A= -3/17+2/3+3/17= (-3/17+3/17)+2/3=0+2/3=2/3

B=-5/21+2/3+1=-5/21+14/21+1=9/21+1=30/21

C=(-1/6+-5/12)+7/12=(-2/12+-5/12)+7/12=-7/12+7/12=0

Answer 6

\(a.A=\left(\frac{-3}{17}+\frac{3}{17}\right)+\frac{2}{3}\)

\(A=0+\frac{2}{3}\)

\(A=\frac{2}{3}\)

\(b.B=\left(\frac{-5}{21}+\frac{2}{3}\right)+1\)

\(B=\left(\frac{-5}{21}+\frac{14}{21}\right)+1\)

\(B=\frac{9}{21}+1\)

\(B=\frac{9}{21}+\frac{21}{21}\)

\(B=\frac{30}{21}\)

\(c.C=\frac{-1}{6}+\left(\frac{-5}{12}+\frac{7}{12}\right)\)

\(C=\frac{-1}{6}+\left(-1\right)\)

\(C=\frac{-7}{6}\)

Answer 7

Mình bị nhầm câu C

\(C=\frac{-1}{6}+\left(\frac{-5}{12}+\frac{7}{12}\right)\)

\(C=\frac{-1}{6}+\frac{1}{6}\)

\(C=0\)