A=\(\dfrac{-2}{9}\)+\(\dfrac{-3}{4}\)+\(\dfrac{3}{5}\)+\(\dfrac{1}{15}\)+\(\dfrac{1}{57}\)+\(\dfrac{1}{3}\)+\(\dfrac{-1}{36}\)
A=(\(\dfrac{-2}{9}\)+\(\dfrac{-3}{4}\)+\(\dfrac{-1}{36}\))+(\(\dfrac{3}{5}\)+\(\dfrac{1}{15}\)+\(\dfrac{1}{3}\))
câu 1 : A=-2/9+-3/4+3/5+1/15+1/57+1/3+-1/36
=(-2/9+-3/4+-1/36)+(3/5+1/15+1/3)
Vậy p/s 1/57 đâu bạn ?
\(\dfrac{-2}{9}-\dfrac{3}{4}+\dfrac{3}{5}+\dfrac{1}{15}+\dfrac{1}{57}+\dfrac{1}{3}-\dfrac{1}{36}\)
\(=\left(-\dfrac{2}{9}-\dfrac{3}{4}-\dfrac{1}{36}\right)+\left(\dfrac{3}{5}+\dfrac{1}{15}+\dfrac{1}{3}\right)+\dfrac{1}{57}\)
\(=\dfrac{-8-27-1}{36}+\dfrac{9+1+5}{15}+\dfrac{1}{57}\)
\(=-\dfrac{36}{36}+\dfrac{15}{15}+\dfrac{1}{57}\)
\(=\dfrac{1}{57}\)
A=−29+−34+35+115+157+13−136A=-29+-34+35+115+157+13-136
→A=(−29+−34+13−136)+(35+115)+157→A=(-29+-34+13-136)+(35+115)+157
→A=(
Gọi ƯCLN(12n+1,30n+2)=d(d>0,d∈Z)ƯCLN(12n+1,30n+2)=d(d>0,d∈Z)
⇒12n+1⋮d,30n+2⋮d⇒12n+1⋮d,30n+2⋮d
⇒60n+5⋮d,60n+4⋮d⇒60n+5⋮d,60n+4⋮d
⇒60n+5−60n−4⋮d⇒60n+5-60n-4⋮d
⇒1⋮d⇒1⋮d
⇒d∈Ư(1)={1,−1}⇒d∈Ư(1)={1,-1}
⇒12n+130n+2
Đúng(0)
Gọi ƯCLN(12n+1,30n+2)=d(d>0,d∈Z)ƯCLN(12n+1,30n+2)=d(d>0,d∈Z)
⇒12n+1⋮d,30n+2⋮d⇒12n+1⋮d,30n+2⋮d
⇒60n+5⋮d,60n+4⋮d⇒60n+5⋮d,60n+4⋮d
⇒60n+5−60n−4⋮d⇒60n+5-60n-4⋮d
⇒1⋮d⇒1⋮d
⇒d∈Ư(1)={1,−1}⇒d∈Ư(1)={1,-1}
⇒12n+130n+2
Đúng(0)
Chứng minh các phân số sau là phân số tối giản với mọi số nguyên n: A=\frac{12n+1}{30n+2}
lúc nãy cháu mình nó trả lời lung tung sory nha bù lè
\(A=\frac{2}{9}+\frac{\left(-3\right)}{4}+\frac{3}{5}+\frac{1}{15}+\frac{1}{57}+\)\(\frac{1}{3}-\frac{1}{36}\)
\(A=\left(\frac{1}{3}-\frac{1}{36}+\frac{2}{9}+-\frac{3}{4}\right)\)\(+\left(\frac{3}{5}+\frac{1}{15}\right)+\frac{1}{57}\)
\(A=\frac{1}{57}\)
Khó quá , em mới lớp 2 thôi.