12.2
12.2+12.8
tinh nhanh
12 x 2 + 12 x 8
= 12 x ( 2 + 8 )
= 12 x 10
= 120
k mifnh nha bajn
\(12\cdot2+12\cdot8\)
\(=12\cdot\left(2+8\right)\)
\(=12\cdot10\)
\(=120\)
tính nhanh:
12.2+12.5
12.2 + 12. 5 = 12 . ( 2 + 5 )
= 12 . 10
= 120
B=-12.2-3.-12+(-2)=12
tìm x biết 4x-12.2^x+32=0
ban coi ki laoi de coi chung de sai do cho 4x
(20.2^4+12.2^4-48.2^2):8^4
( 20.2^4+12.2^4-48.2^2):8^2
(2^4.<20+12>-48.2^2):8^2
=(2^4.32-192):8^2
=320:8^2
=5
(12.2+12.4-12.6):(2+4+6+...+18+20) = ?
(12x2 +12x4 - 12x6) : (2+4+6+....+18+20)
=12 x (2+4-6) : (2+4+6+...+18+20)
=12 x 0 : (2+4+6+...+18+20)
= 0
= ( 12 . 2 + 12 . 4 - 12 . 6 ) : ( 2+4+6+8+...+18+20)
= 12 . ( 2+4-6 ) : ( 2+4+6+8+...+18+20 )
= 12 . 0 : ( 2+4+6+8+...+18+20 )
= 0
thích cho mình nha !
4^x+12.2^x+32=0
Ta có : \(4^x+12.2^x+32=0\)
<=> \(\left(2^x\right)^2+2.6.2^x+36-4=0\)
<=> \(\left(2^x+6\right)^2-4=0\)
<=> \(\left(2^x+6+2\right)\left(2^x+6-2\right)=0\)
<=> \(\left(2^x+8\right)\left(2^x+4\right)=0\)
<=> \(\left[{}\begin{matrix}2^x+8=0\\2^x+4=0\end{matrix}\right.\) <=> \(\left[{}\begin{matrix}2^x=-8\\2^x=-8\end{matrix}\right.\) ( Vô lý )
Vậy phương trình vô nghiệm .
(20.2^4 - 12.2^3 - 48.2^2)^2 : (-8)^3