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16 tháng 9 2021

úm bala alaba trap

đặt A=3+3^2+..+3^8

        =3(1+3+..+3^7)

        \(=3\left[\left(1+3+3^2+3^3\right)+3^4\left(1+3+3^2+3\right)\right]\\ =3\left(40+3^4.40\right)=120.\left(3^4+1\right)\)

do 3^4 chia hết cho 2 nên A chia hết cho 240

 

7 tháng 10 2018

Mủ => mũ nha bạn.  À câu trên bạn sai rồi. Sửa nè

Ta có : \(A=280:\left\{5^2+\left[240:8-\left(5-2\right)^3\right]\right\}\)

\(=280:\left\{25+\left[30-3^3\right]\right\}\)

\(=280:\left\{25+\left[30-27\right]\right\}\) 

Rồi đến đó bạn tiếp tục làm nha!

7 tháng 10 2018

bạn lớp 6 à

9 tháng 10 2019

240-[23+(13+24.3-x)]=132

240-[23+(13+168-x)]=132

240-[23+(181-x)]=132

|

x-8:4-(46-23.2+6.3)=0

\(x-8:4-\left(46-23.2+6.3\right)=0\)

\(x-2-\left(46-46+18\right)=0\)

\(x-2-18=0\)

\(x-2=0+18\)

\(x-2=18\)

\(x=18+2\)

\(x=20\)

7 tháng 4 2021

a) (- 15) . 4 – 240 : 6 + 36 : (- 2) . 3 = - 60 – 40 + (- 18) = - 118

b) (- 2)5 + [(- 69) : 3 + 53] . (- 2) – 8 

= - 32 + (- 23 + 53) . (- 2) - 8

= - 32 + 30 . (- 2) - 8

= - 32 + (- 60) – 8

= - 100

25 tháng 11 2023

1) \(\left(+15\right)+\left(+17\right)=15+17=32\)

2) \(\left(-3\right)+\left(-7\right)=-3-7=-\left(3+7\right)=-10\)

3) \(\left(-25\right)+\left(+4\right)=-25+4=-\left(25-4\right)=-21\)

4) \(\left(-6\right)+\left(-54\right)=-6-54=-\left(6+54\right)=-60\)

5) \(\left(-15\right)+20=20-15=5\)

6) \(\left(-5\right)+8+7+5\)

\(=\left(-5+5\right)+\left(8+7\right)\)

\(=15\)

7) \(\left(-8\right)+\left(-11\right)+\left(-2\right)\)

\(=\left[\left(-8\right)+\left(-2\right)\right]+\left(-11\right)\)

\(=\left(-10\right)+\left(-11\right)\)

\(=-21\)

8) \(15+\left(-5\right)+\left(-14\right)+\left(-16\right)\)

\(=\left[15+\left(-5\right)\right]+\left[\left(-14\right)+\left(-16\right)\right]\)

\(=10+\left(-30\right)\)

\(=-20\)

9) \(\left(-20\right)+\left(-14\right)+3+\left(-86\right)\)

\(=\left[\left(-20\right)+3\right]+\left[\left(-14\right)+\left(-86\right)\right]\)

\(=\left(-17\right)+\left(-100\right)\)

\(=-117\)

10) \(\left(-136\right)+123+\left(-264\right)+\left(-83\right)+240\)

\(=\left[\left(-136\right)+\left(-264\right)\right]+\left[123+\left(-83\right)\right]+240\)

\(=\left(-400\right)+40+240\)

\(=\left(-360\right)+240\)

\(=-120\)

11) \(\left(-596\right)+2001+1999+\left(-404+189\right)\)

\(=\left(-596\right)+2001+1999-404+189\)

\(=\left[\left(-596\right)-404\right]+\left(2001+189\right)+1999\)

\(=\left(-1000\right)+2190+1999\)

\(=1190+1999\)

\(=3189\)

12) \(314+\left(-153\right)+64+121+\left(-247\right)+218\)

\(=\left(314+64+121\right)+\left[\left(-153\right)+\left(-247\right)\right]+218\)

\(=\left(378+121\right)+\left(-400\right)+218\)

\(=499-400+218\)

\(=99+218\)

\(=317\)

\(\text{#}Toru\)

Trả lời:

(-65)-(-37)

= (-65)+37

=-28

(-159)-280:(-7)

=(-159)-(-40)

=(-159)+40

=-119

(-12).\(3^2\)+240:\(\left(-2\right)^2\)

=-108+60

=-48

\(5.\left(-2\right)^3-36:3^2\)

=\(-40-4\)

=\(-44\)

\(128-\left[68+8.\left(35-37\right)^2\right]:\left(-4\right)\)

=\(128-\left[68+8.4\right]:\left(-4\right)\)

=\(128-\left[68+32\right]:\left(-4\right)\)

=\(128-100:\left(-4\right)\)

=\(128-\left(-25\right)\)

=\(153\)

\(-141+3^3+\left(-2\right)^2\)

=\(-141+9+4\)

=\(-132+4\)

=\(-128\)

chúc bạN HOK TỐT

1)(-65)-(-37)=-28

2)(-159)-280:(-7)

=(-159)-(-40)

=-119

3)(-12).3\(^2\)+240:(-2)\(^{^2}\)

=-108+60

=-48

4)5.(-2)\(^3\)-36:3\(^2\)

=-40-4

=-44

5) 128-[68+8.(35-37)2]:(-4)

=128-[68+8.-2\(^2\)]:(-4)

=128-[68+32]:(-4)
=128-100:(-4)

=128-(-25)

=153

6)-141+3\(^3\)+(-2)\(^2\)

=-114+4

=-110

\(\left(-65\right)-\left(-37\right)=\left(-65\right)+37=-\left(65-37\right)=-28\)

\(\left(-159\right)-280\div\left(-7\right)=\left(-159\right)-\left(-40\right)=-119\)

\(\left(-12\right).3^2+240\div\left(-2\right)^2=\left(-12\right).9+240\div4=\left(-108\right)+60=-48\)

\(5.\left(-2\right)^3-36\div3^2=5.\left(-8\right)-36\div9=\left(-40\right)-4=-44\)

\(128-\left[68+8.\left(35-37\right)^2\right]\div\left(-4\right)=128-\left[69+8\left(-2\right)^2\right]\div4\)

\(=128-\left(69+8.4\right)\div4=128-101\div4=128-25,25=102,75\)

\(\left(-141\right)+3^3+\left(-2\right)^2=\left(-141\right)+27+4=\left(-141\right)+31=-110\)

22 tháng 12 2020

240 : 3 : 8 - (x - 50) : 3 = 6

<=> 10 - (x - 50) : 3 = 6

<=> - (x - 50) : 3 = -4

<=> - x + 50 = -12

<=> - x = -62

<=> x = 62

31 tháng 7 2015

a) \(\frac{y}{6}=\frac{2010}{15}\)                              c)  \(x-\frac{1}{3}=\frac{1}{4}\)             e)\(5y-1952=2500-1947\)

\(y=\frac{2010}{15}.6\)                                  \(x=\frac{1}{4}+\frac{1}{3}\)                  \(5y-1952=553\)                                         

\(y=804\)                                           \(x=\frac{7}{12}\)                             \(5y=553+1952\)

                                                                                                                      \(5y=2505\)

                                                                                                                         \(y=2505:5=501\)

 

b) \(x+\frac{1}{2}=\frac{3}{4}\)                                      c)   \(3x+\frac{3}{8}=\frac{1}{2}\)

\(x=\frac{3}{4}-\frac{1}{2}\)                                                \(3x=\frac{1}{2}-\frac{3}{8}\)

\(x=\frac{1}{4}\)                                                              \(3x=\frac{1}{8}\)

                                                                                    \(x=\frac{1}{8}:3\)

                                                                                   \(x=\frac{1}{24}\)

           f)\(\left(8y-1942\right).1947=\left(240-194,2\right).19470\)

              \(\left(8y-1942\right).1947=45,8.19470\)

               \(\left(8y-1942\right)=45,8.19470:1947\)

                 \(8y-1942=45,8.10\)

                 \(8y-1942=458\)

                                      \(8y=458+1942\)

                                        \(8y=2400\)

                                              \(y=2400:8\)

                   \(y=300\)