73*73*28=
a ) 73 x 28 + ........ 73 = 7300
b ) 73 x 28 + ......... + 73 = 7300
c ) 73 x 28 + ......... x 73 = 7300
d ) 73 x 28 + ........ : 73 = 7300
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73 x 28 + ... 73 =7300
\(73\times28+x\times73=7300\)
\(73\times\left(28+x\right)=7300\)
\(28+x=7300:73\)
\(28+x=100\)
\(x=100-28\)
\(x=72\)
= 7300 - 73 * 28
= 5256
= 5256 :73
= 72
So sánh A và B biết:
A = 73^42+1/73^41+1, B=73^29+1/73^28+1
14,65*73+14,65*28-14,65
14,65*73+14,65*28-14,65
=14,65*73+14,65*28-14,65*1
=14,65*(73+28-1)
=14,65*100
=1465
14,65*73+14,65*28-14,65 = 14,65(73+28-1)
=14,65*100
=1465
10) x - [42 + (-28)] = -8
11) (7 - x) - (25 + 7)=- 25
12) (3x - 24). 73 = 2.74
13) ( x – 4)² = 25
14) 24( 2x + 11)² = 42
15) 73x-2 – 3.73 =73 . 4
\(10,\Rightarrow x-14=-8\Rightarrow x=6\\ 11,\Rightarrow7-x-32=-25\\ \Rightarrow-25-x=-25\Rightarrow x=0\\ 12,\Rightarrow3x-16=\dfrac{2\cdot7^4}{7^3}=2\cdot7=14\\ \Rightarrow3x=30\Rightarrow x=10\\ 13,\Rightarrow\left[{}\begin{matrix}x-4=5\\x-4=-5\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=9\\x=-1\end{matrix}\right.\\ 14,\Rightarrow\left(2x+11\right)^2=2^4:2^4=1\\ \Rightarrow\left[{}\begin{matrix}2x+11=1\\2x+11=-1\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=-5\\x=-6\end{matrix}\right.\\ 15,\Rightarrow7^{3x-2}=7^3\cdot4+7^3\cdot3=7^3\cdot7=7^4\\ \Rightarrow3x-2=4\\ \Rightarrow3x=6\Rightarrow x=2\)
10) x - [42 + (-28)] = -8
x - 14 = -8
x = -8 + 14 = 6
11) (7-x) - (25 +7) = -25
(7 -x) - 32 = -25
7 -x = -25 + 32 = 7
x = 7 -7 = 0
12) (3x - 24) . 73 = 2 . 74
(3x - 16) . 343 = 4802
3x - 16 = 4802 : 343= 14
3x = 14 + 16 = 30
x = 30 : 3 =10
13) (x - 4)2 = 25
⇒ 52 = 25
⇒ x - 4 = 5
⇒ x = 5 + 4 =9
14) 24(2x + 11)2 = 42
16(2x + 11)2 = 16
(2x + 11)2 = 16 : 16 = 1
⇒ 2x + 11 = 1
⇒ 2x = 11 + 1 = 12
⇒ x = 12 : 2 = 6
15) 73x-2 - 3.73 = 73 . 4
73x-2 - 1029 = 1372
73x-2 = 1372 + 1029 = 2401
⇒ 74 = 2401
⇒ 3x - 2 = 4
⇒ 3x = 4 + 2 = 6
⇒ x = 6 : 3 =2
Bài 1: Tính
a, 28 - { -13 - [ -11+ ( -12 + 5 ) ] }
b, -39 - { - 46+ [ -11 - ( -21) ] }
c, 73 + { - 49 - [ - 73 - ( 7 2 - 8 ) ] }
d, - 86 - { - 97 + [ - 11 - ( - 28 + 5 ) ] }
a 24
b -3
c 161
d -1
đúng ko bn
kb
B1
a) 28-{-13-[-11+(-12+5)]}=28-{-13-[-11+(-7)]}=28-{-13-[-18]}=28-5=23
b)-39-{-46+[-11-(-21)]}=-39-{-46+10}=-39-(-36)=-3
c)73+{-49-[-73-(72-8)]}=73+{-49-[-73-64]}=73+{-49-[-137]}=73+88=161
d)-86-{-97+[-11-(-28+5)]}=-86-{-97+[-11-(-23)]}=-86-{-97+12}=-86-{-85}=-1
73 . 25 + 28 . 25 - 25
[(6.x-73):2-84].28=5628
\([(6\cdot x-73):2-84]\cdot28=5628\\(6x-73):2-84=5628:28\\(6x-73):2-84=201\\(6x-73):2=201+84\\(6x-73):2=285\\6x-73=285\cdot2\\6x-73=570\\6x=570+73\\6x=643\\x=643:6\\x=\dfrac{643}{6}\\Vậy:x=\dfrac{643}{6}\)
\(\left[\left(6x-73\right):2-84\right]\cdot28=5628\)
\(\left(6x-73\right):2-84=201\)
\(\left(6x-73\right):2=285\)
\(6x-73=570\)
\(6x=643\)
\(x=\dfrac{643}{6}\)
Tìm x:
56−x=28
x−17=73
56−x=28
x=56−28
x=28
x−17=73
x=73 + 17
x=90