\(x.2+\left(-\frac{9}{25}\right)=\frac{2}{5}.\frac{8}{5}\)

\(\Leftrightarrow x.2+\left(-\frac{9}{25}\right)=\frac{16}{25}\)

\(\Leftrightarrow x.2=1\)

\(\Leftrightarrow x=\frac{1}{2}\)

Vậy \(x=\frac{1}{2}\)

x=1/2

\(x.2+\left(-\frac{9}{25}\right)=\frac{2}{5}.\frac{8}{5}\)

\(\Leftrightarrow2x+\left(-\frac{9}{25}\right)=\frac{16}{25}\)

\(\Leftrightarrow2x=\frac{16}{25}+\frac{9}{25}\)

\(\Leftrightarrow2x=1\)

\(\Leftrightarrow x=\frac{1}{2}\)

a)2/13 . 5 - 9/11 . 2/13 - 7/11 . 2/13

=2/13.(5-9/11-7/11)

=2/13.39/11

=6/11.

b)(-1/2)² + 4,25

=1/4+4,25

=1/4+17/4

=9/2.

c)(-2/3)² : ( --2 2/3) -- ( 5/8 -- 5/6 ) + 5.8--45/5.8

= -4/3 : -8/3 - -5/24 + 40 - 72

= -751/24.

a) \(\frac{2^7\cdot9^3}{6^5\cdot8^2}=\frac{2^7\cdot\left(3^2\right)^3}{\left(2\cdot3\right)^5\cdot\left(2^3\right)^2}=\frac{2^7\cdot3^6}{2^5\cdot3^5\cdot2^6}=\frac{3}{2^4}=\frac{3}{16}\)

c) \(\frac{5^4\cdot20^4}{25^4\cdot4^5}=\frac{5^4\cdot\left(2^2\cdot5\right)^4}{\left(5^2\right)^4\cdot\left(2^2\right)^5}=\frac{5^4\cdot2^8\cdot5^4}{5^8\cdot2^{10}}=\frac{1}{2^2}=\frac{1}{4}\)

d) \(\frac{\left(5^4\cdot20^4\right)^3}{125^4}=\frac{5^{12}\cdot20^{12}}{\left(5^3\right)^4}=\frac{5^{12}\cdot\left(2^2\cdot5\right)^{12}}{5^{12}}=2^{24}\cdot5^{12}\)

\(\text{-7129+1478+7129+(-1479)}\)

\(=\text{-7129+7129+1478+(-1479)}\)

\(=0-1=-1\)

\(\text{|-5|.(-7)+4.(-9)}\)

\(=\text{5.(-7)+4.(-9)}\)

\(=\left(-35\right)+\left(-36\right)=-71\)

\(\text{(-4)²+35:(-7)}\)

\(=\text{16+(-5)=11}\)

Mn oi trả lời cho em đi 🙏🙏🙏

em chịu

(-25).(-3).x      Với x=4

(-25).(-3).4=[(-25).4].(-3)

                 =-100.(-3)

                 =300

(-1).(-4).5.8.y   Với y=25

(-1).(-4).5.8.25=(-1).[(-4).25].(5.8)

                       =(-1).(-100).40

                       =100.40=4000

(2ab²):c     Với a=4,b=-6,c=12

[2.4.(-6²)]:12=[2.4.(-36)]:12

                   =-288:12=-24

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