tính nhanh
a) (45.10.56+28.255):(28.54+57.25)
b) (310.11+310.5):(39.24)
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\(a,\dfrac{3^{43}+3^4}{3^{39}+1}\)
\(=\dfrac{3^4\cdot\left(3^{39}+1\right)}{3^{39}+1}\)
\(=3^4\)
\(=81\)
a, A = 27.36+73.99+27.14 - 49.73
= 27(36+14)+73(99 - 49)
= 27.50 + 73.50 = 50(27+73) = 50.100 = 5000
b, B = 4 5 . 10 . 5 6 + 25 5 . 2 8 : 2 8 . 5 4 + 5 7 . 2 5
Ta có: 4 5 = 2 2 5 = 2 2 . 5 = 2 10 ; 25 5 = 5 2 5 = 5 2 . 5 = 5 10
=> 4 5 . 10 . 5 6 + 25 5 . 2 8 = 2 10 . 2 . 5 . 5 6 + 5 10 . 2 8 = 2 11 . 5 7 + 5 10 . 2 8 = 2 8 . 2 3 . 5 7 + 5 7 . 5 3 . 2 8 = 2 8 . 5 7 . 2 3 + 5 3
Ta lại có: 2 8 . 5 4 + 5 7 . 2 5 = 2 5 . 2 3 . 5 4 + 5 4 . 5 3 . 2 5 = 2 5 . 5 4 . 2 3 + 5 3
Suy ra B = 2 8 . 5 7 . 2 3 + 5 3 :[ 2 5 . 5 4 . 2 3 + 5 3 ] = 2 8 . 5 7 : 2 5 . 5 4
= 2 8 : 2 5 . 5 7 : 5 4 = 2 3 . 5 3 = 2 . 5 3 = 10 3 = 1000
a, A = 27.36+73.99+27.14 - 49.73
= 27(36+14)+73(99 - 49)
= 27.50 + 73.50 = 50(27+73) = 50.100 = 5000
b, B = 4 5 . 10 . 5 6 + 25 5 . 2 8 : 2 8 . 5 4 + 5 7 . 2 5
Ta có: 4 5 = 2 2 5 = 2 2 . 5 = 2 10 ; 25 5 = 5 2 5 = 5 2 . 5 = 5 10
=> 4 5 . 10 . 5 6 + 25 5 . 2 8 = 2 10 . 2 . 5 . 5 6 + 5 10 . 2 8 = 2 11 . 5 7 + 5 10 . 2 8 = 2 8 . 2 3 . 5 7 + 5 7 . 5 3 . 2 8 = 2 8 . 5 7 . 2 3 + 5 3
Ta lại có: 2 8 . 5 4 + 5 7 . 2 5 = 2 5 . 2 3 . 5 4 + 5 4 . 5 3 . 2 5 = 2 5 . 5 4 . 2 3 + 5 3
Suy ra B = 2 8 . 5 7 . 2 3 + 5 3 :[ 2 5 . 5 4 . 2 3 + 5 3 ] = 2 8 . 5 7 : 2 5 . 5 4
= 2 8 : 2 5 . 5 7 : 5 4 = 2 3 . 5 3 = 2 . 5 3 = 10 3 = 1000
\(4^{10}.8^{15}=2^{20}.2^{45}=2^{65}\)
\(4^{15}.5^{30}=2^{30}.5^{30}=10^{30}\)
\(27^{16}:9^{10}=3^{48}:3^{20}=3^{28}\)
\(72^3.54^2=2^9.3^6.2^2.3^6=2^{11}.3^{12}\)
\(108^4=2^8.3^{12}\)
\(3^{10}.11+3^{10}.5=3^{10}.\left(11+5\right)=3^{10}.16\)
\(3^9.2^4=3^9.2^4\)
`@` `\text {Ans}`
`\downarrow`
`4^10*8^15`
`= (2^2)^10 * (2^3)^15`
`= 2^20 * 2^45`
`=`\(2^{20+45}=2^{65}\)
`4^15 * 5^30`
`= (2^2)^15 * 5^30`
`= 2^30 * 5^30`
`= (2*5)^30`
`= 10^30`
`27^16 \div 9^10`
`= (3^3)^16 \div (3^2)^10`
`= 3^48 \div 3^20`
`=`\(3^{48-20}=3^{28}\)
`A = `\(72^3\cdot54^2\cdot108^4\)
`= 2^9 * 3^6 * 3^4 * 3^2 * 2^2 * 3^8 * 3^4 * 2^4 * 2^4`
`=`\(\left(2^9\cdot2^2\cdot2^4\cdot2^4\right)\cdot\left(3^6\cdot3^4\cdot3^2\cdot3^8\cdot3^4\right)\)
`= 2^19 * 3^24`
`B = 3^10 * 11 + 3^10 * 5 + 3^9 * 2^4`
`= 3^9 * (11*3 + 5*3 + 2^4)`
`= 3^9 * (33 + 15 + 16)`
`= 3^9 * 64`
`= 27^3 * 4^3`
`= (27 * 4)^3`
`= 108^3`
a: \(68^2+64\cdot68+32^2\)
\(=\left(68+32\right)^2\)
=10000
b: \(51\cdot49=50^2-1=2499\)
\(a,=72\cdot\left(-200\right)=-14400\\ b,=\left(125\cdot8\right)\left[\left(-5\right)\left(-20\right)\right]=1000\cdot100=1000000\)
\(a,=\left(123-123\right)+\left(54+46\right)=100\\ b,=\left(-64+64\right)+\left(71-111\right)=-40\)
`a)=(6xx8xx5xx3)/(5xx5xx6xx3xx8)=(1)/5`
`b)=5/8xx(9/7+5/7)`
`=5/8xx2=10/8=5/4`
A,\(\dfrac{6x8x15}{25x6x24}=\dfrac{6x8x5x3}{5x5x6x3x8}=\dfrac{1}{5}\)