a, (135-35).(-37)+37.(-42-58)

= 100.(-37)+37.(-100)

= 100.(-37)+(-37).100

= (-37).(100+100)

= (-37).200

= -7400

b, -65.(87-17)-87.(17-65)

= -65.70-87.(-48)

= -4550+4176

=-374

c, [3.(-2)-(-8)].(-7)-(-2).(-5)

= [(-6)+8].(-7)+(-10)

= 2.(-17)

= -34

a) (135 - 35) . (-37) + 37 . (-42 - 58)

= 100 . 0 . (-100)

= 0

b) -65 . (87 - 17) - 87 . (17 - 65)

= -65 . 70 - 87 . (-48)

= -4550 - 135

= -4415

300

300

= 300 

a.35 x 34 + 35 x 38 + 65 x 75 + 45 x 65

= 35 x (34 + 38) + 65 x 75 + 65 x 45

= 35 x     72      + 65 x (75+45)

= 35 x 72 + 65 x 120

= 35 x 72 + 65 x (72 + 48)

= 35 x 72 + 65 x 72 + 65 x 48

= (35+65) x 72 + 65  x 48

=   100 x 72 + 65 x 48

=      7200   +    3120

=           10320

b.39 x 8 + 60 x 2 + 21 x 8

=39 x 8 + 15 x 4 x 2 +21 x 8

= 39 x 8 + 15 x 8 + 21 x 8

=(39 + 15 + 21) x 8

=      75            x 8

=             600

c.58 x 75 + 58 x 50 - 58 + 25

= 58 x 75 + 58 x 50 - 58 x 1 + 25

= 58 x(75+50-1)+25

= 58 x   124     + 25

=    7192          + 25

=              7217

d.125 x 98 - 125 x 46 - 52 x 25

= 25 x 5 x 98 - 25 x 5 x 46 - 25 x 52

= 25 x 490 - 25 x 230 - 25 x 52

= 25 x (490 - 230 - 52)

= 25 x      208

=       5200

ham mo chi qua

câu 1) 

\(\dfrac{-12}{18}+\left(\dfrac{-21}{35}\right)=\dfrac{-19}{15}\)
câu 2) 

\(-\dfrac{3}{21}+\dfrac{6}{42}=0\)
câu 3)

\(-\dfrac{18}{24}+\dfrac{15}{21}=-\dfrac{1}{28}\)
câu 4) 

\(\dfrac{1}{6}+\dfrac{2}{5}=\dfrac{17}{30}\)
câu 5) 

\(\dfrac{3}{5}+\left(-\dfrac{7}{4}\right)=-\dfrac{23}{20}\)
câu 6) 

\(\left(-2\right)+\left(\dfrac{-5}{8}\right)=\dfrac{-21}{8}\)
câu 7) 

\(\dfrac{1}{-8}+\left(-\dfrac{5}{9}\right)=-\dfrac{49}{72}\)
câu 8) 

\(\dfrac{4}{13}+\dfrac{12}{39}=\dfrac{8}{13}\)
câu 9) 

\(\dfrac{1}{21}+\dfrac{1}{28}=\dfrac{1}{12}\)
câu 10) 

\(-\dfrac{3}{29}+\dfrac{16}{58}=\dfrac{5}{29}\)
câu 11) 

\(\dfrac{8}{40}+\left(-\dfrac{36}{45}\right)=-\dfrac{3}{5}\)
câu 12) 

\(-\dfrac{8}{18}+\left(-\dfrac{15}{27}\right)=-1\)
câu 13) 

\(\dfrac{13}{30}+\left(-\dfrac{1}{5}\right)=\dfrac{7}{30}\)
câu 14) 

\(\dfrac{2}{21}+\dfrac{1}{28}=\dfrac{11}{84}\)
câu 15) 

\(5+\left(-\dfrac{3}{4}\right)=\dfrac{17}{4}\)
câu 16) 

\(\dfrac{18}{24}+\dfrac{45}{-10}=-\dfrac{15}{4}\)

a)= 2021.2021-2020.(2021+1)
  = 2021.(2020+1)-2020.(2021+1)
  = (2021.2020)+2021-(2020.2021)-2020
  = 1

b) B= (1+2-3-4)+(5+6-7-8)+(9+10-11-12)...........+(2017+2018-2019-2020)+2021
    B= -4+(-4)+....................(-4)+2021
    B= -4x505+2021
    B= -2020 + 2021
    B = 1

a) \(36.\left(-57\right)-57.64\)

\(=36.\left(-57\right)+\left(-57\right).64=\left(-57\right).\left(36+64\right)\)

\(=\left(-57\right).100=-5700\)

b)\(32.\left(-17\right)+\left(-18\right).17-50.13\)

\(=\left(-32\right).17+\left(-18\right).17-50.13\)

\(=17.\left(-32-18\right)-50.13=17.\left(-50\right)+\left(-50\right).13\)

\(=\left(-50\right).\left(17+13\right)=\left(-50\right).30=-150\)

c)\(-\left(-35\right)+12-|-35|-42\)

\(=35+12-35-42=12-42=-30\)

d)\(\left(-15-12\right):\left(-3\right)^2+5-13.\left(-2\right)+\left(-64\right):2^3\)

\(=-27:9+5+26-64:8=-3+5+26-8=20\)

e)\(\left(135-35\right).\left(-37\right)+37.\left(-42-58\right)=100.\left(-37\right)+37.\left(-100\right)\)

\(=\left(-100\right).37+37.\left(-100\right)=\left(-100\right).\left(37+37\right)\)

\(=\left(-100\right).74=-7400\)

Chúc em học tốt!!!!!!

Giải thích gõ mỏi tay lắm nên mình chỉ ghi đáp án thôi nha !!!

a)-5700

b)-1500

c)-30

d)20

d)-7400

Answer:

Bài 1: 

\(\left(135-35\right).\left(-37\right)+37.\left(-42-58\right)\)

\(=100.\left(-37\right)+37.\left(-100\right)\)

\(=\left(-3700\right)+\left(-3700\right)\)

\(=-7400\)

\(-65.\left(87-17\right)-87.\left(17-65\right)\)

\(=\left(-65\right).87-\left(-65\right).17-87.17+87.65\)

\(=-\left(-65\right).17-87.17\)

\(=17.\left(65-87\right)\)

\(=-374\)

\([3.\left(-2\right)-\left(-8\right)].\left(-7\right)-\left(-2\right).\left(-5\right)\)

\(=[\left(-6\right)+8].\left(-7\right)-\left(-2\right).\left(-5\right)\)

\(=2.\left(-7\right)-10\)

\(=-24\)

Bài 2:

\(\left(-55\right).\left(-25\right).\left(-8\right)\)

\(=\left(-55\right).[\left(-25\right).\left(-8\right)]\)

\(=\left(-55\right).200\)

\(=-11000\)

\(\left(-1\right).\left(-2\right).\left(-3\right).\left(-4\right).\left(-5\right).10\)

\(=[\left(-1\right).10].[\left(-2\right).\left(-5\right)].[\left(-3\right).\left(-4\right)]\)

\(=\left(-10\right).10.12\)

\(=-1200\)