2 x( X +56 )-13 =(65 x 12)
BT1 : Tính nhanh nếu có thể :
a) -25 + 8 + 12 + 25
b) -87 + ( -750 ) + 2018 - 13 + 750
c) ( 45 + 12 - 13 ) - ( 45 - 13 + 12 )
d) -15 x 56 + 43 x ( -15 ) - 15
e) -62 x 32 - 65 x 47 - 21 x 65
g) 24 x ( 16 - 5) - 16 x ( 24 - 5 )
h) 5 - 10 + 15 - 20 + ............+ 2015 - 2020
BT3 : Tìm n thuộc Z biết :
a) 3n + 2 chia hết n - 1
b) n mũ 2 + 5 chia hết n+1
c) n + 1 chia hết n mũ 2 - 2
a 25 + 8 + 12 + 25 = 70 b 87 + [ - 750 ] + 2018 - 13 + 750 = 2842 c [ 45 + 12 - 13 ] - [ 45 - 13 + 12 ] = 90 minh tinh gom bn ah
TÌM X
A=(275000+357000+4130000+12510)
A2+(3A+9):1245=?
?A+18-48+48-18+32-32+56+65+(-56)+(-65)=X
(-12)^2.x=56-[(-10).13.x]
Tìm x: (-12)2 . x = 56 + 10 . 13 . x
(-12)2 . x = 56 + 10 . 13 . x
=> 144 . x = 56+130 .x
=> 144x - 130x = 56
=>14x =56
=>4
(-12)2.x=56+10.13.x
=> 144.x=56+130.x
=> 144x-130x=56
=> x(144-130)=56
=> 14x=56
=> x=4
<=> 144 . x = 56 + 10 . 13x
<=> 144x = 56 + 130x
<=> 144x - 130x = 56
<=> 14x = 56
=> x = 56 : 14 = 4
Vậy x = 4
đúng 100%
Tìm x
a) x/-8 = 5/4
b) -13/x = -65/10
c)-6/5 = -12/x
d) x-2/2= 8/x-2
a)
`x/(-8)=5/4`
`=>x*4=5*(-8)`
`=>4x=-40`
`=>x=-40:4`
`=>x=-10`
b)
`(-13)/x=(-65)/10`
`=>(-13)/x=(-13)/2`
`=>x=2`
c)
`(-6)/5=(-12)/x`
`<=>(-12)/10=(-12)/x`
`<=>x=10`
d)
`(x-2)/2=8/(x-2)`
`=>(x-2)(x-2)=8*2`
`=>(x-2)^2=16`
`=>x-2=4` hoặc`x-2=-4`
`=>x=4+2` hoặc `x=-4+2`
`=>x=6` hoặc `x=-2`
`x/(-8) = 5/4`
`=> 4x=5.(-8)`
`=>4x=-40`
`=>x=-40:4`
`=>x=-10`
__
`-13/x =-65/10`
`=> -65x=-130`
`=>x=-130:(-65)`
`=>x= 2`
__
`-6/5 =-12/x`
`=> -6x=-12.5`
`=> -6x= -60`
`=>x=-60:(-6)`
`=>x=10`
__
`(x-2)/2 = 8/(x-2)`
`=>(x-2)^2=2.8`
`=>(x-2)^2=16`
`=> (x-2)^2=+-4^2`
\(\Rightarrow\left[{}\begin{matrix}x-2=4\\x-2=-4\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=6\\x=-2\end{matrix}\right.\)
Tìm x:
(-12)mũ 2 . x = 56 + 10 . 13 . x
-12^2.x=56+10.13.x
<=>144x=56+130x
<=>144x-130x=56
<=>14x=56
<=>x=4
Vậy x=4
(-12)2.x=56+10.13.x
144x=56+130x
144x-130x=56
14x=56
X=4
Vay.......
(-12) 2 . x = 56 + 10 . 13 . x
144x = 56 + 130x
144x - 130x = 56
14x = 56
=> x = 56 : 14
=> x = 4
(-12)2.x = 56 + 10 . 13 . x
tìm x
\(\left(-12\right)^2.x=56+10.13.x\)
\(144x=130x+56\)
\(144x-130x=56\)
\(14x=56\)
\(x=4\)
(-12)2.x=56-[(-10).13.x)
(-12)2.x=56-[(-10).13.x]
(-12)2.x=56-[-10.13.x]
144.x=56-[-130x]
144x=56+130x
144x-130x=56
14x=56
x=56:14
x=4
Vậy x=4