327.1530.(-4)16
(-15)30.811
a, 7/15 + 8/15 + 9/16 +7/16=
b, 4/7 * 5/6 + 4/7 * 1/6
a) \(\dfrac{7}{15}+\dfrac{8}{15}+\dfrac{9}{16}+\dfrac{7}{16}\)
\(=\left(\dfrac{7}{15}+\dfrac{8}{15}\right)+\left(\dfrac{9}{16}+\dfrac{7}{16}\right)\)
\(=1+1\)
\(=2\)
b) \(\dfrac{4}{7}\times\dfrac{5}{6}+\dfrac{4}{7}\times\dfrac{1}{6}\)
\(=\dfrac{4}{7}\times\left(\dfrac{5}{6}+\dfrac{1}{6}\right)\)
\(=\dfrac{4}{7}\times1\)
\(=\dfrac{4}{7}\)
(7/15 + 8 / 15 ) + ( 9/16 +7/16)
1 + 1
2
4/7 . ( 5/6+1/6)
4/7 . 1
4/7
a) \(=1+1=2\)
b) \(=\dfrac{4}{7}\left(\dfrac{5}{6}+\dfrac{1}{6}\right)=\dfrac{4}{7}\)
Tính bằng cách thuật tiện
a,19/35+15/!9+16/35+23/19+4/15+11/15
b,4/17-7/15+13/17-8/15+5/8-7/16
Rút gọn biểu thức sau:
D=\(\frac{15^{16}+15^{12}+...+15^4+1}{15^{18}+15^{16}+...+15^2+1}\)
1) -145.(13 - 57) + 57.(10 -145)
2) 17.(15 - 16) + 16.( 17- 20)
3) -38.(25 - 4) + 25.(-4 + 38 )
4) 23.(145 - 17) - 145.(23 - 6)
5) 24.(15 - 4) + 4.(24 - 15)
6) 199.(15 - 17) - 199.(-17 + 5)
7) -39.(5 - 99) + 99.(10 - 39)
1: \(=-145\cdot13+145\cdot57+57\cdot10-57\cdot145=-1315\)
2: \(=17\cdot15-17\cdot16+16\cdot17-16\cdot20=255-320=-65\)
3: \(=-38\cdot25+38\cdot4-25\cdot4+25\cdot38=13\cdot4=52\)
4: \(=23\cdot145-23\cdot17-145\cdot23+145\cdot6=479\)
5: \(=24\cdot15-24\cdot4+4\cdot24-4\cdot15=360-60=300\)
6: \(=199\left(15-17+17-5\right)=199\cdot10=1990\)
7: \(=-39\cdot5+39\cdot99+99\cdot10-99\cdot39=795\)
1: =−145⋅13+145⋅57+57⋅10−57⋅145=−1315=−145⋅13+145⋅57+57⋅10−57⋅145=−1315
2: =17⋅15−17⋅16+16⋅17−16⋅20=255−320=−65=17⋅15−17⋅16+16⋅17−16⋅20=255−320=−65
3: =−38⋅25+38⋅4−25⋅4+25⋅38=13⋅4=52=−38⋅25+38⋅4−25⋅4+25⋅38=13⋅4=52
4: =23⋅145−23⋅17−145⋅23+145⋅6=479=23⋅145−23⋅17−145⋅23+145⋅6=479
5: =24⋅15−24⋅4+4⋅24−4⋅15=360−60=300=24⋅15−24⋅4+4⋅24−4⋅15=360−60=300
6: =199(15−17+17−5)=199⋅10=1990=199(15−17+17−5)=199⋅10=1990
7: =−39⋅5+39⋅99+99⋅10−99⋅39=795
Rút gọn biểu thức sau:
D=\(\frac{15^{16}+15^{12}+...+15^4+1}{15^{18}+15^{16}+...+15^2+1}\)
Tính hợp lí
1) -145.(13 - 57) + 57.(10 -145)
2) 17.(15 - 16) + 16.( 17- 20)
3) -38.(25 - 4) + 25.(-4 + 38 )
4) 23.(145 - 17) - 145.(23 - 6)
5) 24.(15 - 4) + 4.(24 - 15)
6) 199.(15 - 17) - 199.(-17 + 5)
7) -39.(5 - 99) + 99.(10 - 39)
Bài 1 (0,5 điểm). Phân số nào dưới đây bằng phân số 4/5 ?
A. 20/16 B. 18/15 C. 16/30 D. 16/15
Không có cái nào cả?
Nếu muốn đúng thì giải thích nè:
Ta quy đồng:
\(\dfrac{4}{5}=\dfrac{4x4}{5x4}=\dfrac{16}{20}\)
Đó, hoặc cái lớn hơn nha!!!
\(\dfrac{4}{3.5}\) + \(\dfrac{8}{5.9}\) + \(\dfrac{12}{9.15}\)+.......+
\(\dfrac{32}{x(x+16)}\) = \(\dfrac{16}{15}\)
\(\dfrac{32}{x(x+16)}\) = \(\dfrac{16}{15}\)
\(\dfrac{HeLp}{me}\) \(\dfrac{nguyễn}{đức}{Trí}\)
\(\dfrac{4}{3.5}+\dfrac{8}{5.9}+\dfrac{12}{9.15}+...+\dfrac{32}{x\left(x+16\right)}=\dfrac{16}{15}\)
\(2.\left(\dfrac{2}{3.5}+\dfrac{4}{5.9}+\dfrac{6}{9.15}+..+\dfrac{16}{X.\left(X+16\right)}\right)=\dfrac{16}{15}\)
\(\dfrac{1}{3}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{9}+\dfrac{1}{9}-\dfrac{1}{15}+...+\dfrac{1}{X}-\dfrac{1}{X+16}=\dfrac{8}{15}\)
\(\dfrac{1}{X+16}=\dfrac{1}{3}-\dfrac{8}{15}\)
\(\dfrac{1}{X+16}=\dfrac{-1}{5}\)
\(X+16=-5\)
\(X=-21\)
Bài 1 Tìn x : x/16*(2017-1)=2
Bài 2 tìm x : x*15/16-x*4/16=2
Bài 3 Tìm x : 1-(5/4/9+x+7/7/18):15/3/4=0
( Dấu / là dấu gạch phân số Và 5/4/9 ; 15/3/4 ; 7/7/18 Là hỗn số )
bài2 \(x\times\dfrac{15}{16}-x\times\dfrac{4}{16}=2\)
\(x\times\dfrac{11}{16}=2\)
\(x=2:\dfrac{11}{16}\)
\(x=\dfrac{32}{11}\)
Bài 1 :
\(\dfrac{x}{16}\times\left(2017-1\right)=2\)
\(\dfrac{x}{16}\times2016=2\)
\(\dfrac{x}{16}=\dfrac{2}{2016}\)
\(x=\dfrac{2}{2016}\times16\)
\(x=\dfrac{1}{63}\)
1- (5\(\dfrac{4}{9}\) +x+7\(\dfrac{7}{18}\)) : 15\(\dfrac{3}{4}\) = 0
1- (\(\dfrac{49}{9}+x+\dfrac{133}{18}\)) : \(\dfrac{63}{4}=0\)
(\(\dfrac{49}{9}+\dfrac{133}{18}\)+\(x\) ) : \(\dfrac{63}{4}\) = 1 - 0
(\(\dfrac{77}{6}\) + \(x\) ) : \(\dfrac{63}{4}\) = 1
\(\dfrac{77}{6}+x\) = 1 x \(\dfrac{63}{4}\)
\(\dfrac{77}{6}\) + \(x\) = \(\dfrac{63}{4}\)
\(x\) = \(\dfrac{63}{4}\) - \(\dfrac{77}{6}\)
\(x=\) \(\dfrac{35}{12}\)
4/5 bằng
a 20/16 b 16/20 c16/15 d12/16