Tích bằng cách thuận tiên nhất
a)21/11 × 22/17 × 68/63
b)5/14 * 7/13 * 26/25
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21/11 x 22/17x68/63
= 7x3x2x11x4x17 / 11x17x7x3x3
=8/3
5/14x7/13x26/25
=5x7x26 / 14x13x25
= 5x7x13x2 / 7x2x13x5x5
=1/5
a; \(\dfrac{21}{11}\) x \(\dfrac{22}{17}\) x \(\dfrac{68}{63}\)
= \(\dfrac{21\times11\times2\times17\times4}{11\times17\times21\times3}\)
= \(\dfrac{11\times17\times21}{11\times17\times21}\) x \(\dfrac{2\times4}{3}\)
= 1 x \(\dfrac{8}{3}\)
= \(\dfrac{8}{3}\)
b; \(\dfrac{5}{14}\) \(\times\) \(\dfrac{7}{13}\) x \(\dfrac{26}{25}\)
= \(\dfrac{5\times7\times2\times13}{7\times2\times13\times5\times5}\)
= \(\dfrac{5\times7\times2\times13}{5\times7\times2\times13}\) x \(\dfrac{1}{5}\)
= 1 x \(\dfrac{1}{5}\)
= \(\dfrac{1}{5}\)
a ) 21/11 * 22/ 17 *68 / 63 = 42 /17 * 68 / 63 = 8 / 3
b) 5 / 14 * 7 / 13 * 26 / 25 = 5/ 26 * 26 / 25 = 1/ 5
a) \(\frac{21}{11}\times\frac{22}{17}\times\frac{68}{63}=\frac{7\times3\times11\times2\times17\times4}{11\times17\times3\times3\times7}=\frac{8}{3}\)
b) \(\frac{5}{14}\times\frac{7}{13}\times\frac{26}{25}=\frac{5\times7\times13\times2}{2\times7\times13\times5\times5}=\frac{1}{5}\)
\(\frac{21}{11}\cdot\frac{22}{17}\cdot\frac{68}{63}=\frac{7\cdot3\cdot2\cdot11\cdot17\cdot4}{11\cdot17\cdot7\cdot3\cdot3}=\frac{8}{3}\)
\(\frac{5}{14}\cdot\frac{7}{13}\cdot\frac{26}{25}=\frac{5\cdot7\cdot13\cdot2}{7\cdot2\cdot13\cdot5\cdot5}=\frac{1}{5}\)
số nào giống thì gạch đi nhé