Tìm x
( 2 . x - 15 ) . 11 = 11
( x - 2010 ) . 2009 = x - 2010
( x - 5 ) . ( x - 7 ) = 0
( x - 11 ) . ( x - 2018 ) = 0
. = dấu nhân
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A = 2011 x (2009 + 1) - 1/ 2011 x 2009 + 2010
A = 2011 x 2009 + 2011 x 1 - 1/2011 x 2009 + 2010
A = 2011 x 2009 + 2010/2011 x 2009 + 2010
A = 1
B.
a) (2010 - x)(x + 2021) = 0
<=> \(\left[{}\begin{matrix}2010-x=0\\x+2021=0\end{matrix}\right.\)<=> \(\left[{}\begin{matrix}x=2010\\x=-2021\end{matrix}\right.\)
b) (x - 2)^2 + 5(x - 2) = 0
<=> x^2 - 4x + 4 + 5x - 10 = 0
<=> x^2 + x - 6 = 0
<=> x^2 - 2x + 3x - 6 = 0
<=> x(x - 2) + 3(x - 2) = 0
<=> (x + 3)(x - 2) = 0
<=> \(\left[{}\begin{matrix}x+3=0\\x-2=0\end{matrix}\right.\) <=> \(\left[{}\begin{matrix}x=-3\\x=2\end{matrix}\right.\)
ai lam guip toi cau nay voi mai toi nop bai roi
so sanh 2 phan so sau bang cach nahnh nhat: 2007/2008 voi 2008/2009
2010 x 2010 - 2009 x 2011
= ( 2011 - 2010 ) x 2010 - 2009 x 2011
= 2011 x 2010 - 1 x 2010 - 2009 x 2011
= 2011 x ( 2010 - 2009 ) - 1 x 2010
= 2011 x 1 - 2010
= 2011 - 2010
= 1
( 456 x 11 + 912 ) x 37 : ( 13 x 74 )
= ( 456 x 11 + 456 x 2 ) x 37 : ( 13 x 74 )
= [ 456 x ( 11 + 2 ) ] x 37 : ( 13 x 74 )
= [ 456 x 13 ] x 37 : ( 13 x 74 )
= 13 x 456 x 37 : ( 13 x 37 x 2 )
= 13 x 37 x 2 x 228 : ( 13 x 37 x 2 )
= ( 13 x 37 x 2 ) x 228 : ( 13 x 37 x 2 )
= ( 13 x 37 x 2 ) : ( 13 x 37 x 2 ) x 228
= 1 x 228
= 228
(44 x 52 x 60) : (11 x13 x 15 )
= [ ( 4 x 11 ) x ( 4 x 13 ) x ( 4 x 15 ) ] : (11 x13 x 15 )
= [ 4 x 11 x 4 x 13 x 4 x 15 ] : (11 x13 x 15 )
= [ ( 4 x 4 x 4 ) x ( 11 x 13 x 15 ) ] : (11 x13 x 15 )
= 64 x (11 x13 x 15 ) : (11 x13 x 15 )
= 64 x 1
= 64
a) 2010 x 2010 - 2009 x 2011
= 2010 x 2010 - [ 2009 x ( 2010 +1) ]
=2010 x 2010 - 2009 x 2010 - 2009
=2010( 2010 - 2009 ) -2009
= 2010 -2019
= 1
c) ( 44 x 52 x60 ) : (11x13x15)
\(\frac{44\cdot52\cdot60}{11\cdot13\cdot15}=\frac{4\cdot11\cdot4\cdot13\cdot4\cdot15}{11\cdot13\cdot15}=64\)
B) (456 x 11 +912) x 37 : ( 13 x 74 )
= \(\frac{\left(456\cdot11+912\right)\cdot37}{13\cdot74}=\frac{\left[456\left(11+2\right)\right]\cdot37}{13\cdot37}=\frac{456\cdot13}{13\cdot2}=\frac{456}{2}=228\)
Nhớ k mik nha bn
Bài 1:
a)12,5 x (-5/7) + 1,5 x (-5/7)
=-5/7*(12,5+1,5)
=-5/7*14
=-10
b)(-1/4) x (6|2/11) + 3|9/11 x (-1/4)
=-1/4*(68/11+42/11)
=-1/4*10
=-5/2
c tương tự
d)\(\frac{9^8\cdot4^3}{27^4\cdot6^5}=\frac{\left(3^2\right)^8\cdot\left(2^2\right)^3}{\left(3^3\right)^4\cdot\left(2\cdot3\right)^5}=\frac{3^{16}\cdot2^6}{3^{12}\cdot2^5\cdot3^5}=\frac{3^{16}\cdot2^5\cdot2}{3^{16}\cdot3^1\cdot2^5}=\frac{2}{3}\)
Bài 2:
a)Ta có:
2800=(28)100=256100
8200=(82)100=64100
Vì 256100>64100 =>2800>8200
b)Ta có:
1245=(123)15=172815
Vì 62515<172815 =>62515<1245
(2.x - 15) . 11 = 11
2.x - 15 = 11 : 11
2.x - 15 = 1
2.x = 1 + 15
2.x = 16
x = 16 : 2 = 8
(x - 5) . (x - 7) = 0
\(\Rightarrow\orbr{\begin{cases}x-5=0\\x-7=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=5\\x=7\end{cases}}\)
(x - 2010) . 2009 = x - 2010
2009x - 4038090 = x - 2010
2009x - x = 4038090 - 2010
2008x = 4036080
x = 4036080 : 2008
x = 2010
(x - 11) .(x - 2018) = 0
\(\Rightarrow\orbr{\begin{cases}x-11=0\\x-2018=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=11\\x=2018\end{cases}}\)