X mũ 2098-500 × Y mũ x+67=45170000
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\(7\cdot4^x=112\)
\(\Rightarrow4^x=\dfrac{112}{7}\)
\(\Rightarrow4^x=16\)
\(\Rightarrow4^x=4^2\)
\(\Rightarrow x=2\)
_____
\(2\cdot5^{x-3}=250\)
\(\Rightarrow5^{x-3}=\dfrac{250}{2}\)
\(\Rightarrow5^{x-3}=125\)
\(\Rightarrow5^{x-3}=5^3\)
\(\Rightarrow x-3=3\)
\(\Rightarrow x=3+3\)
\(\Rightarrow x=6\)
____
\(12:\left\{400:\left[500-\left(5^3+5^2\cdot7\right)\right]\right\}+10\)
\(=12:\left\{400:\left[500-\left(125+25\cdot7\right)\right]\right\}+10\)
\(=12:\left\{400:\left[500-\left(125+175\right)\right]\right\}+10\)
\(=12:\left[400:\left(500-300\right)\right]+10\)
\(=12:\left(400:200\right)+10\)
\(=12:2+10\)
\(=6+10\)
\(=16\)
\(7\cdot4^x=112\)
\(\Rightarrow4^x=112:7\)
\(\Rightarrow4^x=16\)
\(\Rightarrow4^x=4^2\)
\(\Rightarrow x=2\)
Vậy \(x=2.\)
\(---\)
\(2\cdot5^{x-3}=250\)
\(\Rightarrow5^{x-3}=250:2\)
\(\Rightarrow5^{x-3}=125\)
\(\Rightarrow5^{x-3}=5^3\)
\(\Rightarrow x-3=3\)
\(\Rightarrow x=3+3\)
\(\Rightarrow x=6\)
Vậy \(x=6.\)
\(---\)
\(12:\left\{400:\left[500-\left(5^3+5^2\cdot7\right)\right]\right\}+10\)
\(=12:\left\{400:\left[500-\left(125+175\right)\right]\right\}+10\)
\(=12:\left\{400:\left[500-300\right]\right\}+10\)
\(=12:\left\{400:200\right\}+10\)
\(=12:2+10\)
\(=6+10\)
\(=16\)
#\(Toru\)
a) 4.25-12.5+170:10
=100-60+17
=40+17
=57
b) (7+33:32).4-3
=(7+3).4-3
=10.4-3
=40-3
=37
c) 12:{400:[500-(125+25.7)]}
=12:{400:[500-(125+175)]}
=12:{400:[500-300]}
=12:{400:200}
=12:2
=6
d) 168+{[2.(24+32)-2560]:72}
=168+{[2.(16+9)-1]:49}
=168+{[2.25-1]:49}
=168+{[50-1]:49}
=168+{49:49}
=168+1
=169
a) x(x+1)=2+4+6+8+...+2500
x(x+1)=(2500+2).1250:2
x(x+1)=1563750
Ta thấy: x và x+1 là 2 số liên tiếp
Mà x(x+1)=1563750=>x=1250;x+1=1251
Vậy x=1250
b) x-3=12:{390:[500-(5^3+7^2.5)]}
x-3=12:[390:(500-254.64)]
x-3=12:(390:245.35)
x-3=12:1.58
x-3=7.54
=>x=10.5
Vậy x=10.5
c) x+3^3.12=3^3.19
=>x=2.46
Vậy x=2.46
a)<=>
A,=(x+y)(x-y)=x^2-y^2
x=(-1/2)^5:(1/2)^4=-1/2
x^2=1/4
y=8^2/(-2)^5=-2
y^2=4
A=1/4-4=-15/4
a) \(\dfrac{10^{12}+5^{11}.2^9-5^{13}.2^8}{4.5^5.10^6}\)
\(=\dfrac{2^{12}.5^{12}+5^{11}.2^9-5^{13}.2^8}{2^2.5^5.2^6.5^6}\)
\(=\dfrac{2^{12}.5^{12}+5^{11}.2^9-5^{13}.2^8}{2^8.5^{11}}\)
\(=\dfrac{\left(2^8.5^{11}\right)\left(2^4.5+2-5^2\right)}{2^8.5^{11}}\)
\(=2^4.5+2-5^2\)
\(=57\)
b) \(\dfrac{\left[5\left(x-y\right)^4-3\left(x-y\right)^3+4\left(x-y\right)^2\right]}{\left(y-x\right)^2}\)
\(=\dfrac{\left(x-y\right)^2\left[5\left(x-y\right)^2-3\left(x-y\right)+4\right]}{\left(y-x\right)^2}\)
\(=\dfrac{\left(x^2+y^2-2xy\right)\left[5\left(x-y\right)^2-3\left(x-y\right)+4\right]}{\left(y^2+x^2-2xy\right)}\)
\(=5\left(x-y\right)^2-3\left(x-y\right)+4\)
c) \(\dfrac{\left(x+y\right)^5-2\left(x+y\right)^4+3\left(x+y\right)^3}{-5\left(x+y\right)^3}\)
\(=\dfrac{\left(x+y\right)^3\left[5\left(x+y\right)^2-2\left(x+y\right)+3\right]}{-5\left(x+y\right)^3}\)
\(=\dfrac{5\left(x+y\right)^2-2\left(x+y\right)+3}{-5}\)
a) ( 5x - y )( 25x2 + 5xy + y2 ) = ( 5x )3 - y3 = 125x3 - y3
b) ( x - 3 )( x2 + 3x + 9 ) - ( 54 + x3 ) = x3 - 33 - 54 - x3 = -27 - 54 = -81
c) ( 2x + y )( 4x2 - 2xy + y2 ) - ( 2x - y )( 4x2 + 2xy + y2 ) = ( 2x )3 + y3 - [ ( 2x )3 - y3 ]= 8x3 + y3 - 8x3 + y3 = 2y3
d) ( x + y )2 + ( x - y )2 + ( x + y )( x - y ) - 3x2 = x2 + 2xy + y2 + x2 - 2xy + y2 + x2 - y2 - 3x2 = y2
e) ( x - 3 )3 - ( x - 3 )( x2 + 3x + 9 ) + 6( x + 1 )2
= x3 - 9x2 + 27x - 27 - ( x3 - 33 ) + 6( x2 + 2x + 1 )
= x3 - 9x2 + 27x - 27 - x3 + 27 + 6x2 + 12x + 6
= -3x2 + 39x + 6
= -3( x2 - 13x - 2 )
f) ( x + y )( x2 - xy + y2 ) + ( x - y )( x2 + xy + y2 ) - 2x3
= x3 + y3 + x3 - y3 - 2x3
= 0
g) x2 + 2x( y + 1 ) + y2 + 2y + 1
= x2 + 2x( y + 1 ) + ( y2 + 2y + 1 )
= x2 + 2x( y + 1 ) + ( y + 1 )2
= ( x + y + 1 )2
= [ ( x + y ) + 1 ]2
= ( x + y )2 + 2( x + y ) + 1
= x2 + 2xy + y2 + 2x + 2y + 1