Tính : 73 - 3|x + 2| = - 47
Những câu hỏi liên quan
Thực hiện phép tính
a) 97 x 24 + 6 x 437 x 2 + 3 x 369 x4
b) 37 x 213 + 86 x 37 + ( 73 x 47 - 68 x 47 ) : 47
c) 49 + 51 x ( 98 - 49 ) + 27 x ( 62 + 37 ) + 73 x ( 43 + 56 )
Bài 5*: Tính nhanh:
10000 - 47 x 72 - 47 x 28 3457 - 27 x 48 - 48 x 73 + 6543
=
1000 - 47 . 72 - 47 .28
= 47 . ( 1000 - 72 -28 )
= 47 .0
=0
3457 - 27 . 48 - 48 .73 + 6543
=3457 - 48 . (27 + 73 ) + 6543
= 3457 - 4800 + 6543
= 5200
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Tính : 73 - 3|x + 2| = - 47
\(73-3\left|x+2\right|=-47\)
th1: \(x+2\ge0\Leftrightarrow x\ge-2\)
\(\Rightarrow73-3\left|x+2\right|=-47\Leftrightarrow73-3\left(x+2\right)=-47\)
\(\Leftrightarrow73-3x-6=-47\Leftrightarrow-3x=-47-73+6=-114\)
\(\Leftrightarrow x=\dfrac{-114}{-3}=38\left(tmđk\right)\)
th2: \(x+2< 0\Leftrightarrow x< -2\)
\(\Rightarrow73-3\left|x+2\right|=-47\Leftrightarrow73-3\left(-x-2\right)=-47\)
\(\Leftrightarrow73+3x+6=-47\Leftrightarrow3x=-47-73-6=126\)
\(\Leftrightarrow x=\dfrac{126}{3}=-42\left(tmđk\right)\)
vậy \(x=38;x=-42\)
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\(73-3\left|x+2\right|=-47\)
\(3\left|x+2\right|=73-\left(-47\right)\)
\(3\left|x+2\right|=120\)
\(\left|x+2\right|=40\)
\(\Rightarrow\left[{}\begin{matrix}x+2=40\\x+2=-40\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=38\\x=-42\end{matrix}\right.\)
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Tính : 73 - 3|x + 2| = - 47
\(73-3\left|x+2\right|=-47\)
th1: \(x+2\ge0\Leftrightarrow x\ge-2\)
\(\Rightarrow73-3\left|x+2\right|=-47\Leftrightarrow73-3\left(x+2\right)=-47\)
\(\Leftrightarrow73-3x-6=-47\Leftrightarrow-3x=-47-73+6=-114\)
\(\Leftrightarrow x=\dfrac{-114}{-3}=38\left(tmđk\right)\)
th2: \(x+2< 0\Leftrightarrow x< -2\)
\(\Rightarrow73-3\left|x+2\right|=-47\Leftrightarrow73-3\left(-x-2\right)=-47\)
\(\Leftrightarrow73+3x+6=-47\Leftrightarrow3x=-47-73-6=126\)
\(\Leftrightarrow x=\dfrac{126}{3}=-42\left(tmđk\right)\)
vậy \(x=38;x=-42\)
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Tính : 73 - 3|x + 2| = - 47
\(73-3\left|x+2\right|=-47\)
th1: \(x+2\ge0\Leftrightarrow x\ge-2\)
\(\Rightarrow73-3\left|x+2\right|=-47\Leftrightarrow73-3\left(x+2\right)=-47\)
\(\Leftrightarrow73-3x-6=-47\Leftrightarrow-3x=-47-73+6=-114\)
\(\Leftrightarrow x=\dfrac{-114}{-3}=38\left(tmđk\right)\)
th2: \(x+2< 0\Leftrightarrow x< -2\)
\(\Rightarrow73-3\left|x+2\right|=-47\Leftrightarrow73-3\left(-x-2\right)=-47\)
\(\Leftrightarrow73+3x+6=-47\Leftrightarrow3x=-47-73-6=126\)
\(\Leftrightarrow x=\dfrac{126}{3}=-42\left(tmđk\right)\)
vậy \(x=38;x=-42\)
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73 - 3|x + 2| = - 47
3|x + 2| = 73 - (- 47)
3|x + 2| = 120
|x + 2| = 120 ÷ 3
|x + 2| = 40
=> x + 2 = 40 ; - 40
Trường hợp 1:
x + 2 = 40
x = 40 - 2
x = 38
Trường hợp 2:
x + 2 = - 40
x = - 40 - 2
x = - 42
Vậy x = 38 ; x = - 42
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Tính : 73 - 3|x + 2| = - 47
\(73-3\left|x+2\right|=-47\)
th1: \(x+2\ge0\Leftrightarrow x\ge-2\)
\(\Rightarrow73-3\left|x+2\right|=-47\Leftrightarrow73-3\left(x+2\right)=-47\)
\(\Leftrightarrow73-3x-6=-47\Leftrightarrow-3x=-47-73+6=-114\)
\(\Leftrightarrow x=\dfrac{-114}{-3}=38\left(tmđk\right)\)
th2: \(x+2< 0\Leftrightarrow x< -2\)
\(\Rightarrow73-3\left|x+2\right|=-47\Leftrightarrow73-3\left(-x-2\right)=-47\)
\(\Leftrightarrow73+3x+6=-47\Leftrightarrow3x=-47-73-6=126\)
\(\Leftrightarrow x=\dfrac{126}{3}=-42\left(tmđk\right)\)
vậy \(x=38;x=-42\)
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\(73-3\left|x+2\right|=-47\)
\(\Rightarrow3\left|x+2\right|=26\)
\(\Rightarrow\left|x+2\right|=\dfrac{26}{3}\)
\(\Rightarrow\left[{}\begin{matrix}x+2=\dfrac{26}{3}\Rightarrow x=\dfrac{20}{3}\\x+2=\dfrac{-26}{3}\Rightarrow x=\dfrac{-32}{3}\end{matrix}\right.\)
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bài 7:tính nhanh
a (145 x 99+145)-(143 x 102-143) b,54 x 47 - 47 x 53 - 20 -27
c, 10000 - 47 x 72 - 47 x 28 d, 3457 - 27 x 48 - 48 x 73 + 6543
a) \(\left(145\times99+145\right)-\left(143\times102-143\right)\)
\(=\left[145\times\left(99+1\right)\right]-\left[143\times\left(102-1\right)\right]\)
\(=\left(145\times100\right)-\left(143\times101\right)\)
\(=14500-14443\)
\(=57\)
b) \(54\times47-47\times53-20-27\)
\(=47\times\left(54-53\right)-20-27\)
\(=47-20-27\)
\(=0\)
c) \(10000-47\times72-47\times28\)
\(=10000-47\times\left(72+28\right)\)
\(=10000-47\times100\)
\(=10000-4700\)
\(=5300\)
d) \(3457-27\times48-48\times73+6543\)
\(=\left(3457+6543\right)-48\times\left(27+73\right)\)
\(=10000-48\times100\)
\(=10000-4800\)
\(=5200\)
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Bài 1 Tính hợp lý :
a) 2020-( 249+ 2020) +( 249 - 573)
b) |- 257| + (-3)° - (18+ 257)
c) 25( 85- 47) -85(47+25)
d) 39. 73- 73( - 61)
Bài 2 : Tìm số nguyên x biết : a) 15-5(x+2) = -30
b) (x+2)mũ 2 + 5 = 105
c) |2x-5| -(-6) = 11
d) 3x - 5 chia hết cho x +2
e) 3x +7chia hết cho 2x +1
1,
a,\(2020-\left(249+2020\right)+\left(249-573\right)\)
\(=2020-249-2020+249-573\)
\(=-573\)
b,\(\left|-257\right|+\left(-3\right)^0-\left(18+257\right)\)
\(=257+1-18-257\)
\(=1-18=-17\)
\(c,25.\left(85-47\right)-85.\left(47+25\right)\)
\(=25.85-25.47-47.85+85.25\)
\(=85.\left(25-47+25\right)-25.47\)
\(=85.3-25.47\)
\(=-920\)
2,
\(a,15-5.\left(x+2\right)=-30\)
\(=>5.\left(x+2\right)=15+30=45\)
\(=>x+2=\frac{45}{5}=9\)
\(=>x=7\)
\(b,\left(x+2\right)^2+5=105\)
\(=>\left(x+2\right)^2=100\)
\(=>\left(x+2\right)^2=10^2\)
\(=>x+2=10\)
\(=>x=8\)
\(c,\left|2x-5\right|-\left(-6\right)=11\)
\(=>\left|2x-5\right|=11-6=5\)
\(=>\orbr{\begin{cases}2x-5=5\\2x-5=-5\end{cases}}\)
\(=>\orbr{\begin{cases}2x=5-5=0\\2x=-5+5=0\end{cases}=>x=0}\)
Tính nhanh
32 x 27+ 47 x 73 + 27 x 15
\(32\times27+47\times73+27\times15\)
\(=\left(32\times27+27\times15\right)+47\times73\)
\(=27\times\left(32+15\right)+47\times73\)
\(=27\times47+47\times73\)
\(=47\times\left(27+73\right)\)
\(=47\times100\)
\(=4700\)
Học tốt
\(=32\cdot27+27\cdot15+47\cdot73\)
\(=27\cdot\left(32+15\right)+47\cdot73\)
\(=27\cdot47+47\cdot73\)
\(=47\cdot\left(27+73\right)\)
\(=47\cdot100\)
\(=4700\)
32x27+47x73+27x15
=27x (32+15)+47x73
=27x47+47x73
=47x(27+73)
=47x100=4700
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