a) -72.17+72.31 - 36 . 228

 = -72.17 + 72. 31 - 36.2.114

 = -72 .17 + 72 . 31 -72 . 114

 = -72. ( 17-31+114)

 = -72 . 100

 = -7200

b) ..........

 = -7 . ( 16-36.9) -(-125) 

 = -7 . ( 16-324) +125

 =-7 . ( -308) +125

 = 2156+125

 = 2281

$a)$

$-72.17+72.31-36.228$

$=-72.17+72.31-36.2.114$

$=-72.17+72.31-72.114$

$=72(31-17-114)$

$=72.(-100)=-7200$

$b)$$-7.[{(-2)}^4+(-36):(-3^2)]-{(-5)}^3$

$=-7.[16-36:(-9)]+125$

$=-7.[16--4]+125$

$=-7.20+125$

$=-140+125$

$=-15$

$c)$$(57-725)-(605-53)$

$=57-725-605+53$

$=(57+53)-120$

$=110-120=-10$

$a)$

$-72.17+72.31-36.228$

$=-72.17+72.31-36.2.114$

$=-72.17+72.31-72.114$

$=72(31-17-114)$

$=72.(-100)=-7200$

a.(64 - 32 ) :8 = 32 : 8 = 4 

b. 36 x 2 x7 + 36 x 86

= 36 x (14 + 86)

= 36 x 100

= 3600

   68:8 - 32 : 8

= ( 68 - 32): 8

=    36 : 8

=    4,5

72 x 7 + 36 x 86

= 72 x 7 + 36 x 2 x 43

= 72 x 7 + 72 x 43

= 72 x ( 7 + 43)

= 72 x 50

= 3600

a) 64 : 8 - 32 : 8

=( 64 - 32 ) : 8 

=      32      :  8

=         4

b. 36 x 2 x7 + 36 x 86

= 36 x (14 + 86)

= 36 x 100

= 3600

C1:

a. 786 x ( 32 +68)

= 786 x  100

= 78600

b. 2904 x 15 + 2904 x 35

= 43560 + 101640

= 145200

c.436 x 72 - 436 x 42

= 31392 - 18312

= 13080

d.194 x (87-7)

= 194 x 80

=15520

e.3332 : (4x49)

= 3332 : 196

= 17

f. 72 : 9 : 8

= (72 : 9) :8

= 1

g. (15 x 24) : 6

= 360 :6

= 60

m. 25 x(36 :9)

= 25 x 4

= 100

Cách 2:

a.786 x 32 + 786 x 68

= 25152 + 53448

= 78600

b. 2904 x ( 15 + 35)

= 2904 x 50

= 145200

c.436 x (72 -42)

= 436 x 30

= 13080

d.194 x 87 - 194 x7

= 16878 - 1358

= 15520

e. 3332 : (4 x 49)

= 3332 : 4 : 49

= 833 : 49 = 17

f. 72 : 9 :8

= 72 : (9 x8)

= 72 : 72

=1

g. (15 x 24) :6 

= 15 x (24 :6)

= 15 x 4

= 60

m. 25 x (36 :9)

= ( 25 x36 ):9

= 900 : 9

=100

câu c là j vậy e chỗ 34,72 32,28 và câu e chỗ 12,34 (5,36)

c)34, 72 32,28 : 5 – 57,25 – 36, 05 : 2

=(34,72+32,28):5-(57,25-36,05):2

=67 : 5 - 21,2 : 2

=13,4 - 10,6

=2,8

e)5, 36.12, 34 ( 5, 36).2, 34

=5,36.12,34−5,36.2,34

=5.36.(12,34−2,34)

=5,36.10

=53,6

\(a,=\left(73-27\right)\left(73^2+73\cdot27+27^2\right)=46\cdot8029=369334\\ b,=\left(63-27\right)\left(63+27\right)+\left(72-18\right)\left(72+18\right)\\ =100\cdot36+54\cdot100=100\left(36+54\right)=100\cdot90=9000\\ c,=\left(105-5\right)^3=100^3=1000000\)

a) \(5x-18=72\)

\(5x=72+18\)

\(5x=100\)

\(x=100\div5\)

\(x=20\)

b) \(\left(x-36\right)-32=0\)

\(x-36=32\)

\(x=32+36\)

\(x=68\)

c) \(156-\left(x+6\right)=82\)

\(x+6=156-82\)

\(x-6=74\)

\(x=74+6\)

\(x=80\)

d) \(2^x=16\)

\(2^x=2^4\)

=> x = 4

=72-36/32

=72-9/8

=72-1.125

=70.875

72 - 36 : 32 = 72 - ( 36 :32 )

                 = 72 - 4

                 = 68 .

   72 - 36 : 32

= 72 - ( 36 : 32 )

= 72 - 1,125

= 70,875

Chúc bn hok tốt ~