a)  3 4 = 6 8 < 6 7

b)  17 − 21 = 51 − 63 > 51 − 31

bài 1 :

a)\(2,5.16,27.4+7,3=\left(2,5.4\right).16,27+7,3=10.16,27+7,3\)

\(=162,7+7,3=170\)

b) \(\frac{2}{3}+\frac{3}{4}-\frac{5}{6}=\left(\frac{2}{3}-\frac{5}{6}\right)+\frac{3}{4}=\frac{-1}{6}+\frac{3}{4}=\frac{7}{12}\)

c) \(17,6-5,3+16,8-7,6+15,3-6,8\)

\(=\left(17,6-7,6\right)+\left(-5,3+15,3\right)+\left(16,8-6,8\right)\)

\(=10+10+10=30\)

d)\(\frac{38}{11}+\left(13,16+\frac{6}{11}\right)=\frac{38}{11}+13,16+\frac{6}{11}\)

\(=\left(\frac{38}{11}+\frac{6}{11}\right)+13,16=4+13,16=17,16\)

\(2,45.46+8.0,75+54.2,45+0,5.8\\ =\left[2,45.46+54.2,45\right]\)

\(+\left[8.0,75+0,5.8\right]=\left[2,45.\left(46+54\right)\right]+\left[8.\left(0,75+0,5\right)\right]\)

\(=\left(2,45.100\right)+\left(8.1,25\right)=245+10=255\)

 bài 2 :

a) .....

b) \(1-\left(12,5+x-4,25\right):21,75=0\)

\(\Rightarrow1-\left(12,5+x-4,25\right)=21,75\)

\(\Rightarrow12,5+x-4,25=-20,75\\ \Rightarrow12,5+x=-16,5\)

\(\Rightarrow x=-29\)

cậu có thể tham khảo bài làm trên đây ạ, mn ai thấy đúng thì cho mk xin 1 t.i.c.k đúng ạ ,thank nhiều

a ) 3 4 = 6 8 < 6 7 b ) 17 − 21 = 51 − 63 > 51 − 31

c ) − 4 9 = 12 27 < − 12 52 = − 3 13 d ) − 4 − 11 = 12 33 > 12 38 = − 6 − 19

Co j góc lệch cùng trời cuối đất cú mèo

a)  − 4 9 = − 12 27 < − 12 52 = − 3 13

b)  − 4 − 11 = 12 33 > 12 38 = − 6 − 19