Question

rút gọn

a)\(\frac{7.25-49}{7.24+21}\)                                                     b)\(\frac{2.\left(-13\right).9.10}{\left(-3\right).4.\left(-5\right).26}\)

Answer 1

a,(7*25-49)/(7*24+21)

=(7*25-7*7)/(7*24+7*3)

=[7(25-7)]/[7(24+3)]

=(7*18)/(7*27)

=2/3

b, Câu b dễ mak, lớp 5 cũng làm được

Answer 2

a , =126/189=2/3

b , =-2340/1560=-3/2

Answer 3

a, \(\frac{7.25-49}{7.24+21}=\frac{7.25-7.7}{7.24+7.3}=\frac{7\left(25-7\right)}{7\left(24+3\right)}=\frac{18}{27}=\frac{2}{3}\)

b, \(\frac{2.\left(-13\right).9.10}{\left(-3\right).4.\left(-5\right).26}=\frac{2.\left(-13\right).\left(-3\right).\left(-3\right).\left(-2\right).\left(-5\right)}{\left(-3\right).2.2.\left(-5\right).\left(-13\right).\left(-2\right)}=\frac{-3}{2}\)

Answer 4

a) \(\frac{7.25-49}{7.24+21}\)= \(\frac{7.25-7.7}{7.24+7.3}\)= \(\frac{7\left(25-7\right)}{7\left(24+3\right)}\)= \(\frac{25-7}{24+3}\)= \(\frac{18}{27}\)= \(\frac{2}{3}\)

b) \(\frac{2.\left(-13\right).9.10}{\left(-3\right).4.\left(-5\right).26}\)= \(\frac{1.\left(-13\right).\left(-3\right).\left(-3\right).2.5}{\left(-3\right).2.\left(-5\right).\left(-2\right).\left(-13\right)}\)= \(\frac{\left(-3\right).\left(-1\right)}{1.\left(-2\right)}\)= \(-\frac{3}{2}\)

Answer 5

a)\(\frac{7\cdot25-49}{7\cdot24+21}=\frac{7\cdot25-7\cdot7}{7\cdot24+7\cdot3}=\frac{7\left(25-7\right)}{7\left(24+3\right)}\)

= \(\frac{25-7}{24+3}=\frac{18}{27}=\frac{2}{3}\)

b) \(\frac{2\cdot\left(-13\right)\cdot9\cdot10}{\left(-3\right)\cdot4\cdot\left(-5\right)\cdot26}=\frac{\left(-1\right)\cdot2\cdot13\cdot3\cdot3\cdot5\cdot2}{1\cdot3\cdot2\cdot2\cdot5\cdot13\cdot2}=\frac{-3}{2}\)

Chúc bn học tốt !