giúp mik với : tính nhanh 7.2*7.2+5.7*2*3.6-18*0.4*2.9
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a: \(=\dfrac{7}{12}\cdot12=7\)
b: \(=\dfrac{3}{8}\cdot\dfrac{25}{7}\cdot56\cdot\left(-4\right)=-300\)
c: \(=\dfrac{3}{7}\cdot\dfrac{7}{3}\cdot\dfrac{2}{5}\cdot20\cdot\dfrac{19}{72}=8\cdot\dfrac{19}{72}=\dfrac{19}{9}\)
d: \(=\dfrac{1}{3}\left(\dfrac{4}{5}+\dfrac{6}{5}\right)=\dfrac{2}{3}\)
X x 7 , 2 + X x 2 , 8 = 12 , 7
X x ( 7 ,2 + 2 , 8 ) = 12 , 7
X x 10 = 12 , 7
X = 12 , 7 : 10
X = 1 , 27
Vậy X = 1, 27
15 , 7 x X - 5 , 7 x X = 0 , 8
X x ( 15 , 7 - 5 ,7 ) = 0 , 8
X x 10 = 0 , 8
X = 0 , 8: 10
X = 0 , 08
Vậy X = 0 , 08
Tk mk nha !!!
5.7 x (179 -130) + (3.4 + 2.3) x (32 + 18) + (7.2 - 1.5)=570
k mk nha mn
(-3.15)*(-7.2)+(3.15)*12.4+4.8.(-3.15)
= ( -3,15 ) . ( -7,2 ) + ( -3,15 ) . ( -12,4 ) + 4,8 . ( -3,15 )
= ( -3,15 ) . [ ( -7,2 ) + ( -12,4 ) + 4,8 ]
= ( -3,15 ) . ( -14,8 )
= 46,62
a) 3,6 x 7,2 - 3,6 x 7,1
= 3,6 x (7,2 - 7,1)
= 3,6 x 0,1
= 0,36
b) 0,15 x 600 = 0,15 x 100 x 6
= 15 x 6
= 90
a) 3,6 x 7,2 - 3,6 x 7,1
= 3,6 x (7,2 - 7,1)
= 3,6 x 0,1
= 0,36
b) 0,15 x 600
= 0,15 x 100 x 6
= 15 x 6
= 90
.(15.2^18-7.2^18)
=2^18.(15-7)
=2^18.8
=2^18.2^3
=2^21
.(-4).2.(-5).25.2009
=[(-4).25].[2.(-5)].2009
=(-100).(-10).2009
=1000.2009
=2009000
.(-3)^12:(-3)^11
=(-3)^12-11
=(-3)
.-3478-(29+271)+478
=(-3478+478)-(29+271)
=(-3000)-300
=-3300
Thấy đúng rhì nhaaa!!
\(\frac{5.4^{15}.9^8-4.3^{17}.8^9}{5.2^{11}.6^{18}-7.2^{28}.27^6}\)\(=\frac{5.\left(2^2\right)^{15}.\left(3^2\right)^8-\left(2^2\right).3^{17}.\left(2^3\right)^9}{5.2^{11}.\left(2.3\right)^{18}-7.2^{28}.\left(3^3\right)^6}\)\(=\frac{5.2^{30}.3^{16}-2^2.3^{17}.2^{27}}{5.2^{11}.2^{18}.3^{18}-7.2^{28}.3^{18}}\)
\(=\frac{5.2^{30}.3^{16}-2^{29}.3^{17}}{5.2^{29}.3^{18}-7.2^{28}.3^{18}}=\frac{2^{28}.3^{16}.\left(5.2^2-2.3\right)}{2^{28}.3^{16}.\left(5.2.3^2-7.3^2\right)}\)
\(=\frac{5.2^2-2.3}{5.2.3^2-7.3^2}=\frac{5.4-6}{5.2.9-7.9}=\frac{20-6}{90-63}\)
\(=\frac{14}{27}\)
\(\frac{5.4^{15}.9^8-4.3^{17}.8^9}{5.2^{11}.6^{18}-7.2^{28}.27^6}=\frac{5.\left(2^2\right)^{15}.\left(3^2\right)^8-2^2.3^{17}.\left(2^3\right)^9}{5.2^{11}.\left(2.3\right)^{18}-7.2^{28}.\left(3^3\right)^6}\)\(=\frac{5.2^{30}.3^{16}-2^2.3^{17}.2^{27}}{5.2^{11}.2^{18}.3^{18}-7.2^{28}.3^{18}}=\frac{5.2^{30}.3^{16}-2^{29}.3^{17}}{5.2^{29}.3^{18}-7.2^{28}.3^{18}}\)\(=\frac{2^{29}.3^{16}.\left(5+2-3\right)}{2^{28}.3^{18}.\left(5+2\right)}\)\(=\frac{2.4}{3^2.7}=\frac{8}{63}\)