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Ta có: \(D=\dfrac{3}{7}\left(\dfrac{13}{-8}-\dfrac{7}{9}\right)-\dfrac{5}{8}\left(\dfrac{3}{7}-\dfrac{-8}{15}\right)\)
\(=\dfrac{3}{7}\cdot\dfrac{-13}{8}-\dfrac{3}{7}\cdot\dfrac{7}{9}-\dfrac{5}{8}\cdot\dfrac{3}{7}-\dfrac{5}{8}\cdot\dfrac{8}{15}\)
\(=\dfrac{-39}{56}-\dfrac{3}{7}\left(\dfrac{7}{9}+\dfrac{5}{8}\right)-\dfrac{1}{3}\)
\(=\dfrac{-137}{84}\)
\(D=\dfrac{3}{7}(\dfrac{13}{-8}-\dfrac{7}{9})-\dfrac{5}{8}(\dfrac{3}{7}-\dfrac{-8}{15})\)
\(=(\dfrac{3}{7}. \dfrac{101}{105}).(\dfrac{-173}{72}-\dfrac{5}{8})\)
\(=\dfrac{101}{245}.\dfrac{-109}{36}\)
\(=\dfrac{593}{4410}\)
\(D=\frac{2}{1.4}+\frac{2}{4.7}+...+\frac{2}{97.100}\)
\(3D=\frac{2.3}{1.4}+\frac{2.3}{4.7}+...+\frac{2.3}{97.100}\)
\(3D=2\left(\frac{3}{1.4}+\frac{3}{4.7}+...+\frac{3}{97.100}\right)\)
\(3D=2\left(1-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+...+\frac{1}{97}-\frac{1}{100}\right)\)
\(3D=2\left(1-\frac{1}{100}\right)\)
\(3D=2\cdot\frac{99}{100}\)
\(3D=\frac{99}{50}\)
\(D=\frac{99}{50}:3\)
\(D=\frac{33}{50}\)
a) (3600 - 36 ) : 18
=3564:18
=198
b) 4.37.6+12.25.2+3.8.38
=24.37+24.25+24.38
=24.(37+25+38)
=24.100
=2400
a)(3600-36):18
=3564:18
=198 nha
b)4.37.6+12.25.2+3.8.38
=(4.6).37+(12.2).25+(3.8).38
=24.37+24.25+24.38
=24.(37+25+38) nha
=24.100
=2400
tick cho mk nha bạn Vũ Lệ Quyên
a.(1950+2555):15=1950:15+2555
=130+2555
=2685
b.(4200-378):21=4200-378:221
=4200-18
=4172
c.(3600-180):36=3600-180:36
=3600-5
=3595
a,(2400+72)x24
=24x2400+72x24
=57600+1728
=59328
b,(3600-180):36
=3600:36+180:36
=100+5
=105
c,(525+315):15
=525:15+315:15
=35+21
=56
d,(1026-741):57
=1026:57-741:57
=18-13
=5
a)(2400+72)x24
=2472.24
=4128
b)(3600-180):36
=3420:36
=95
c,(525+315):15
=840:15
=56
d,(1026-741):57
=285:57
=5
Học Tốt !!!
(2 + 4 + 6 + ...+ 98 + 100) x (36 x 333 - 108 x 111)
= (2 + 4 + 6 + ...+ 98 + 100) x (36 x 3 x 111 - 108 x 111)
= (2 + 4 + 6 + ...+ 98 + 100) x ( 108 x 111 - 108 x 111)
= (2 + 4 + 6 + ...+ 98 + 100) x 0 = 0
36 x 333 - 108 x 111
= ( 36 x 3 ) x ( 333 : 3 ) - 108 x 111
= 108 x 111 - 108 x 111
= 0
d) (3600 – 108) : 36 = 3600: 36 – 108 : 36 = 100 – 3 = 97