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\(91.\left\{195:\left[84-\left(21+16x\right)\right]\right\}=7\)
\(195:\left[84-\left(21+16x\right)\right]=\frac{7}{91}\)
\(195:\left[84-\left(21+16x\right)\right]=\frac{1}{13}\)
\(84-\left(21+16x\right)=195:\frac{1}{13}\)
\(84-\left(24+16x\right)=195.13\)
\(84-\left(24+16x\right)=2535\)
\(24+16x=84-2535\)
\(24+16x=-2451\)
\(16x=-2451-24\)
\(16x=-2475\)
\(x=\frac{-2475}{16}\)
vay \(x=\frac{-2475}{16}\)
Ta co : \(\left|x+25\right|\ge0\forall x\in Z\)
\(\left|-y+5\right|\ge0\forall x\in Z\)
Mà : |x + 25| + |-y + 5| = 0
Nên : \(\hept{\begin{cases}\left|x+25\right|=0\\\left|-y+5\right|=0\end{cases}}\)
\(\Leftrightarrow\hept{\begin{cases}x+25=0\\-y+5=0\end{cases}}\)
\(\Leftrightarrow\hept{\begin{cases}x=-25\\y=5\end{cases}}\)
a) (23.37-11.37):37
=(23-11).37:37
=12.(37:37)
=12.1
=12
b)91.172+91.13-91.85
=91.(172+13-85)
=91.100
=9100
a, ( 23 × 37 - 11 × 37 ) ÷ 37
= 37 × ( 23 - 11 ) ÷ 37
= 37 × 12 ÷ 37
= 444 ÷ 37
= 12
b, 91 × 172 + 91 × 13 - 91 × 85
= 91 × ( 172 + 13 - 85 )
= 91 × 100
= 91000
a) \(\dfrac{7}{5}x\div\left(9-6\dfrac{13}{21}\right)=2\dfrac{13}{25}\)
\(\dfrac{7}{5}x\div\left(9-\dfrac{139}{21}\right)=\dfrac{63}{25}\)
\(\dfrac{7}{5}x\div\dfrac{50}{21}=\dfrac{63}{25}\)
\(\dfrac{7}{5}x=6\)
\(x=\dfrac{30}{7}\)
b) \(\left(1,16-x\right)\times5,25\div\left(10\dfrac{5}{9}-7\dfrac{1}{4}\right)\times2\dfrac{2}{17}=75\%\)
\(\left(1,16-x\right)\times5,25\div\left(\dfrac{95}{9}-\dfrac{29}{4}\right)\times\dfrac{36}{17}=\dfrac{75}{100}\)
\(\left(1,16-x\right)\times5,25\div\dfrac{119}{36}=\dfrac{17}{48}\)
\(\left(1,16-x\right)\times5,25=\dfrac{2023}{1728}\)
\(1,16-x=\dfrac{289}{1296}\)
\(x=0,9370061728\)
52 .(y : 78) = 3380
y : 78 = 3380 : 52
y : 78 = 65
y = 65 . 78
y = 5070
Bài 1 :
a) \(...=5^5:5^4=5\)
b) \(...=7^8:7^9=\dfrac{1}{7}\)
c) \(...=2^{15}:\left(2^6.2^5\right)=2^{15}:2^{11}=2^4=16\)
d) \(...=3^{28}:3^{26}=3^2=9\)
Bài 2 :
a) \(...=3^2.3^3:3^4=3^5:3^4=3\)
b) \(...=10^9-10^9=0\)
c) \(...=5^{10}.5^{30}:5^{12}=5^{40}:5^{12}=5^{28}\)
2x + 5 ⋮ x + 2 <=> 2( x + 2 ) + 1 ⋮ x + 2
Vì 2( x + 2 ) ⋮ x + 2 Để 2( x + 2 ) + 1 ⋮ x + 2 <=> 1 ⋮ x + 2
=> x + 2 là ước của 1 => Ư(1) = { -1 ; 1 }
Ta có : x + 2 = 1 => x = -1
x + 2 = - 1 => x = -3
Vậy x = { -1;'-3 }
nhanh nhoa
10- 2x = 25-3x
10-25 = -3x+2x
-15 = -x
15 = x
Vậy x=15
_Học tốt nha_