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

\(73-3\left|x+2\right|=-47\)

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 \(x=38;x=-42\)

\(73-3\left|x+2\right|=-47\)

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 \(x=38;x=-42\)

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

Chúc Các Bạn Học Tốt

\(73-3\left|x+2\right|=-47\)

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 \(x=38;x=-42\)

\(73-3\left|x+2\right|=-47\)

\(\Rightarrow3\left|x+2\right|=26\)

\(\Rightarrow\left|x+2\right|=\dfrac{26}{3}\)

\(\Rightarrow\left[{}\begin{matrix}x+2=\dfrac{26}{3}\Rightarrow x=\dfrac{20}{3}\\x+2=\dfrac{-26}{3}\Rightarrow x=\dfrac{-32}{3}\end{matrix}\right.\)

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) \(3457-27\times48-48\times73+6543\)

\(=\left(3457+6543\right)-48\times\left(27+73\right)\)

\(=10000-48\times100\)

\(=10000-4800\)

\(=5200\)

\(73-3\left|x+2\right|=-47\)

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 \(x=38;x=-42\)

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,

\(a,15-5.\left(x+2\right)=-30\)

\(=>5.\left(x+2\right)=15+30=45\)

\(=>x+2=\frac{45}{5}=9\)

\(=>x=7\)

\(b,\left(x+2\right)^2+5=105\)

\(=>\left(x+2\right)^2=100\)

\(=>\left(x+2\right)^2=10^2\)

\(=>x+2=10\)

\(=>x=8\)

\(c,\left|2x-5\right|-\left(-6\right)=11\)

\(=>\left|2x-5\right|=11-6=5\)

\(=>\orbr{\begin{cases}2x-5=5\\2x-5=-5\end{cases}}\)

\(=>\orbr{\begin{cases}2x=5-5=0\\2x=-5+5=0\end{cases}=>x=0}\)

\(32\times27+47\times73+27\times15\)

\(=\left(32\times27+27\times15\right)+47\times73\)

\(=27\times\left(32+15\right)+47\times73\)

\(=27\times47+47\times73\)

\(=47\times\left(27+73\right)\)

\(=47\times100\)

\(=4700\)

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