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Câu 1:
a) 2225 và 3150
Ta có:2225=(29)25=51225
3150=(36)25=72925
Vì 51225<72925
Suy ra: 2225<3150
Câu 2:
a)\(25^3:5^2=\left(5^2\right)^3:5^2=5^6:5^2=5^4\)
b)\(\left(\frac{3}{7}\right)^{21}:\left(\frac{9}{49}\right)^6=\left(\frac{3}{7}\right)^{21}:\left[\left(\frac{3}{7}\right)^2\right]^6=\left(\frac{3}{7}\right)^{21}:\left(\frac{3}{7}\right)^{12}=\left(\frac{3}{7}\right)^9\)
c)\(3-\left(-\frac{6}{7}\right)^0+\left(\frac{1}{2}\right)^2:2=3+\frac{1}{4}:2=3+\frac{1}{8}=\frac{25}{8}\)
Câu 3:
a)\(9.3^3.\frac{1}{81}.3^2=3^2.3^3.3^2.\left(\frac{1}{3^4}\right)=3^7:3^4=3^3\)
b)\(4.2^5:\left(2^3.\frac{1}{16}\right)=2^2.2^5:\left(2^3.\frac{1}{2^4}\right)=2^7:\frac{1}{2}=2^8\)
c)\(3^2.2^5.\left(\frac{2}{3}\right)^2=288.\frac{4}{9}=2^7\)
d)\(\left(\frac{1}{3}\right)^3.\frac{1}{3}.9^2=\left(\frac{1}{3}\right)^4.\left(3^2\right)^2=3^4.\left(\frac{1}{3}\right)^4=3^4:3^4=1\)
a) 9 . 33 . 1/81 . 32
=32.33.1/34.32
=33
b) 4 . 25 : (23 . 1/16)
=22.25:(23.1/24)
=22.25:1/2
=22.24
=22+4
=26
c) 32 . 25 . (2/3)2
=32.25.22/32
=25.22
=25+2
=27
d) (1/3)2 . 1/3 . 92
=1/32.1/3.(32)2
=1/32.1/3.34
=1/32.33
=3
=31
x+y+1=0 suy ra x+y=1
Làm câu A nhé B,C tương tự
A= x^2.(x+y-2)-(xy+y^2-2y)+(y+x-1)=0-y.(x+y-2)+1=1
Hok tốt
a) A= 120 : {60 : [(32 + 42 ) - 5 ]}
= 120 : { 60 : [ ( 9 + 16 ) - 5 ] }
= 120 : { 60 : [ 25 - 5 ] }
= 120 : { 60 : 20 }
= 120 : 3
= 40
b) \(B=\frac{1}{2}+\frac{1}{3}-\frac{1}{6}\)
\(B=\frac{1.3}{2.3}+\frac{1.2}{3.2}-\frac{1}{6}\)
\(B=\frac{3}{6}+\frac{2}{6}-\frac{1}{6}\)
\(B=\frac{3+2-1}{6}\)
\(B=\frac{4}{6}=\frac{2}{3}\)