150 - [ 120 - ( 7 - 2² ) ] =

= 150 - [ 120 - ( 7 - 4 ) ]

= 150 - [ 120 - 3 ]

= 150 - 117

= 33

No choice teen uk bn ai cx có lúc nhầm mà. Mik bị suốt

a) x - 7 = 5. 0 => x - 7 = 0 =>x = 7.

b) x: 3 = 47 +13 => x: 3 = 60 => x = 60.3 => x = 180.

c) x :  7 - 7 = 0 hoặc x : 12 - 12 = 0. Do đó x = 49 hoặc x = 144.

d) x : 2 = 150 - 135 => x: 2 = 15 => x = 15.2 => x = 30.

e) 100: x = 140 -120 => 100: x = 20 => x = 100:20 => x = 5.

g) x : 5 = 300 - 273 => x : 5 = 27 =>x = 27.5 => x = 135

a) x - 7 = 5. 0 => x - 7 = 0 =>x = 7.

b) x: 3 = 47 +13 => x: 3 = 60 => x = 60.3 => x = 180.

c) x :  7 - 7 = 0 hoặc x : 12 - 12 = 0. Do đó x = 49 hoặc x = 144.

d) x : 2 = 150 - 135 => x: 2 = 15 => x = 15.2 => x = 30.

e) 100: x = 140 -120 => 100: x = 20 => x = 100:20 => x = 5.

g) x : 5 = 300 - 273 => x : 5 = 27 =>x = 27.5 => x = 135

           Bài làm :

\(a\text{)}...\Leftrightarrow\orbr{\begin{cases}x\div7-7=0\\x.3-12=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x\div7=7\\x.3=12\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=49\\x=4\end{cases}}\)

\(b\text{)}\Leftrightarrow...\Leftrightarrow x\div2=15\Leftrightarrow x=15.2=30\)

\(c\text{)}...\Leftrightarrow100\div x=20\Leftrightarrow x=100\div20=5\)

\(d\text{)}...\Leftrightarrow x\div5=27\Leftrightarrow x=27.5=135\)

         7.x + 2.x = 927

\(\Leftrightarrow\)( 7 + 2).x =927

\(\Leftrightarrow\)9.x = 927

\(\Leftrightarrow\)x = 927 : 9

\(\Leftrightarrow\)x = 103

Vậy x = 103

          3(x-2)+150=240

\(\Leftrightarrow\)3(x-2)=240-150

\(\Leftrightarrow\)3(x-2)=90

\(\Leftrightarrow\)x-2=90:3

\(\Leftrightarrow\)x-2=30

\(\Leftrightarrow\)x=30+2

\(\Leftrightarrow\)x=32

Vậy x=32

          ( x + 13 ) : 5 = 120

\(\Leftrightarrow\)x + 13 = 120 \(\times\)5

\(\Leftrightarrow\)x + 13 = 600

\(\Leftrightarrow\)x = 600 - 13

\(\Leftrightarrow\)x = 587

Vậy x = 587

          360:(x-7)=90

\(\Leftrightarrow\)x-7=360:90

\(\Leftrightarrow\)x-7=40

\(\Leftrightarrow\)x=40+7

\(\Leftrightarrow\)x=47

Vậy x=47

                                 7.x + 2.x = 927

                                 x.(7 + 2) = 927

                                 x.9 = 927

                                 x = 927 : 9

                                 x = 103

                             Vậy x = 103

                     3(x - 2) + 150 = 240

                    3(x - 2) = 240 - 150

                    3.(x - 2) = 90

                    x - 2 = 90 : 3 = 30

                    x = 30 + 2 = 32

                  Vậy x = 32

                 (x + 13) : 5 = 120

                 x + 13 = 120 x 5 = 600

                x = 600 - 13 = 587

                Vậy x = 587

              360:(x - 7) = 90

                    x - 7 = 360 : 90 = 4

                   x = 4 + 7 = 11

                   Vậy x = 11

             Ủng hộ mk nha !!! ^_^

a)\(\left(\frac{1}{24.25}+\frac{1}{25.26}+...+\frac{1}{29.30}\right).120+x:\frac{1}{3}=-4\)

\(\Rightarrow\left(\frac{1}{24}-\frac{1}{25}+\frac{1}{25}-\frac{1}{26}+...+\frac{1}{29}-\frac{1}{30}\right).120+x:\frac{1}{3}=-4\)

\(\Rightarrow\left(\frac{1}{24}-\frac{1}{30}\right).120+x:\frac{1}{3}=-4\)

\(\Rightarrow\frac{1}{120}.120+x:\frac{1}{3}=-4\)

\(\Rightarrow1+x:\frac{1}{3}=-4\)

\(\Rightarrow x:\frac{1}{3}=-4-1=-5\)

\(\Rightarrow x=-5.\frac{1}{3}=\frac{-5}{3}\)

b)\(1\frac{3}{5}+\left(\frac{\frac{2}{7}+\frac{2}{17}+\frac{2}{37}}{\frac{5}{7}+\frac{5}{17}+\frac{5}{37}}\right).x=\frac{16}{5}\)

\(\Rightarrow\frac{8}{5}+\left[\frac{2.\left(\frac{1}{7}+\frac{1}{17}+\frac{1}{37}\right)}{5.\left(\frac{1}{7}+\frac{1}{17}+\frac{1}{37}\right)}\right].x=\frac{16}{5}\)

\(\Rightarrow\frac{8}{5}+\frac{2}{5}.x=\frac{16}{5}\)

\(\Rightarrow\frac{2}{5}.x=\frac{16}{5}-\frac{8}{5}=\frac{8}{5}\)

\(\Rightarrow x=\frac{8}{5}:\frac{2}{5}=\frac{8}{5}.\frac{5}{2}=\frac{8}{2}=4\)

\(\Rightarrow x=4\)

(-150-120) : (-3^2) + 21.(-2) - 8^9 : 2^24

= -270       :      9    + (-42)    -       8

=        -30               + (-42)    -      8

=                  -72                   -       8

=                            -80