Sách Giáo Khoa

a) (37 - 17).(-5) + 23.(-13 - 17)
 = 20.(-5) + 23.(-30)
 = (-100) + (-690)
 = -790

b) (-57).(67 - 34) - 67.(34 - 57)
 = (-57).33 - 67.(-23)
 = -1881 + 1541
 = -340
   
hoặc:
   (-57).(67 - 34) - 67.(34 - 57)
 = (-57).67 – (-57).34 – 67.34 + 67.57
 = [67.(-57) + 67.57] – [(-57).34 + 67.34]
 = 67(-57 + 57) - 34(-57 + 67)
 = 67.0 - 34.10
 = 0 - 

a) (37 - 17).(-5) + 23.(-13 - 17)

= 20.(-5) + 23.(-30)

= (-100) + (-690) = -790

b) (-57).(67 - 34) - 67.(34 - 57)

= (-57).33 - 67.(-23)

= -1881 + 1541

= -340

hoặc: (-57).(67 - 34) - 67.(34 - 57)

= (-57).67 – (-57).34 – 67.34 + 67.57

= [67.(-57) + 67.57] – [(-57).34 + 67.34]

= 67(-57 + 57) - 34(-57 + 67)

= 67.0 - 34.10

= 0 - 340

= -340

\(a,\left(37-17\right).\left(-5\right)+23.\left(13-17\right)\)

\(=20.\left(-5\right)+23.\left(-4\right)\)

\(=-100-92\)

\(=-192\)

\(b,\left(-57\right).\left(67-34\right)-67\left(34-57\right)\)

\(=\left(-57\right).33-67.\left(-23\right)\)

\(=-1881+1541\)

\(=-340\)

a) 20.(-5)+23.(-30)

=-100+(-690)

=-790

b)(-57).33-67.(-23)

=-1881-(-1541)

=-340

a, (37-17). (-5) +23 . (-13-17)

=20. (-5) +23. (-30)

= -100-690

= -790

b,(-57) . (67-34)-67.(34-57)

=(-57).33-67 .(-23)

= -1881 + 1541

= -340

a, ( 37 - 17 ) . ( -5 ) + 23 . ( -13 - 17 )                              b, ( -57 ) . ( 67 - 34 ) - 67 . (34 -57 )

= 20 . ( -5 ) + 23 . 4                                                          =-57 . 69 + 57 . 34 - 67 . 34 + 67 . 57 

= -100 + (-690 )                                                               = 57 . 34 - 67 . 34

= -790                                                                            = 34 . ( 57 - 67 )

                                                                                     = 34 . ( -10 )

                                                                                    = -340

nho k cho minh nhieu nha

Cách 1:                                                                                               

a) (37 - 17).(-5) + 23.(-13-17)

=     20.(-5) + 23.(-30)

=     (-100) + (-690)

=           -790

b) (-57).(67 - 34) - 67.(34 - 57)

=       (-57).33 - 67.(-23)

=        1881 -   1541

=             340

Cách 2:

a) (37 - 17).(-5) + 23.(-13 - 17)

=   - 37.5 + 17.5 - 23.13 - 23.17

=   (17.5 - 23.17) - (37.5 + 23.13)

=     17.(5 - 23) - (185 + 299)

=     17.(-18) - 484

=         -306 - 484

=              -790

b) (-57).(67 - 34) - 67.(34 - 57)

= -57.67 + 57.34 - 67.34 + 67.57

= (67.57 - 57.67) + (57.34 - 67.34)

=            34.(57 - 67)

=            34.(-10)

=             -340

Tính:

a) (37 - 17) . (-5) +23 . ( -13 - 17)

=20.18.-30

=-10800

b) (-57) . (67-34) - 67 . (34 - 57)

=(-57).33-67.(-23)

=(-1881)-(-1541)

= -340

a là -790

b là -340

a)(37-17).(-5)+23.(-13-17)=-790

b)(-57).(67-34)-67.(34-57)=-340

tk mình nha

a. = 20 x (-5) + 23 x (-30)

    = -100 - 690

    = -790

b. (-57) x 33 - 67 x (-23)

= -1881 + 1541

= -340

a, 20.(-5)+23.(-30)

=(-100)+(-30)

=(-130)

trả lời sao mà không hiểu chút nào!?!?!?

49\(\frac{8}{23}\) - (5\(\frac{7}{32}\) + 14\(\frac{8}{23}\))

= 49\(\frac{8}{23}\) - 5\(\frac{7}{32}\) - 14\(\frac{8}{23}\)

= (49\(\frac{8}{23}\) - 14\(\frac{8}{23}\)) - 5\(\frac{7}{32}\)

= 35 - 5 - \(\frac{7}{32}\)

= 30 - \(\frac{7}{32}\)

= \(\frac{960}{32}\) - \(\frac{7}{32}\)

= 953/32

Câu b:

71\(\frac{38}{45}\) - (43\(\frac{8}{45}\) - 1\(\frac{17}{57}\))

= 71\(\frac{38}{45}\) - 43\(\frac{8}{45}\) - 1\(\frac{17}{57}\)

= 28\(\frac{30}{45}\) - 1\(\frac{17}{57}\)

= 28\(\frac23\) - 1\(\frac{17}{57}\)

= \(\frac{86}{3}\) - \(\frac{74}{57}\)

= \(\frac{1634}{57}\) - \(\frac{74}{57}\)

= \(\frac{1560}{57}\)

= \(\frac{520}{19}\)