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4 tháng 7 2016

(1/24x25 + 1/25x26 + ... + 1/29x30) x 120 + y : 1/3 = -4

(1/24 - 1/25 + 1/25 - 1/26 + ... + 1/29 - 1/30) x 120 + y x 3 = -4

(1/24 - 1/30) x 120 + y x 3 = -4

1/120 x 120 + y x 3 = -4

=> 1 + y x 3 = -4

=> y x 3 = -4 - 1

=> y x 3 = -5

=> y = -5/3

Vậy x = -5/3

Ủng hộ mk nha ^_-

4 tháng 7 2016

(1/24x25 + 1/25x26 + ... + 1/29x30) x 120 + y : 1/3 = -4

(1/24 - 1/25 + 1/25 - 1/26 + ... + 1/29 - 1/30) x 120 + y x 3 = -4

(1/24 - 1/30) x 120 + y x 3 = -4

1/120 x 120 + y x 3 = -4

=> 1 + y x 3 = -4

=> y x 3 = -4 - 1

=> y x 3 = -5

=> y = -5/3

Vậy x = -5/3

T_I_C_K mk nha

8 tháng 2 2019

Trả lời zùm đi

8 tháng 2 2019

éo biết

2 tháng 6 2017

a) \(\dfrac{2}{3}x-\dfrac{1}{2}=\dfrac{1}{10}\)

\(\dfrac{2}{3}x=\dfrac{1}{10}+\dfrac{1}{2}=\dfrac{3}{5}\)

\(x=\dfrac{3}{5}:\dfrac{2}{3}=\dfrac{9}{10}\)

b) \(\dfrac{39}{7}:x=13\)

\(x=\dfrac{\dfrac{39}{7}}{13}=\dfrac{3}{7}\)

c) \(\left(\dfrac{14}{5}x-50\right):\dfrac{2}{3}=51\)

\(\dfrac{14}{5}x-50=51\cdot\dfrac{2}{3}=34\)

\(\dfrac{14}{5}x=34+50=84\)

\(x=\dfrac{84}{\dfrac{14}{5}}=30\)

d) \(\left(x+\dfrac{1}{2}\right)\left(\dfrac{2}{3}-2x\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x+\dfrac{1}{2}=0\\\dfrac{2}{3}-2x=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{1}{2}\\x=\dfrac{1}{3}\end{matrix}\right.\)

e) \(\dfrac{2}{3}x-\dfrac{1}{2}x=\dfrac{5}{12}\)

\(\dfrac{1}{6}x=\dfrac{5}{12}\)

\(x=\dfrac{5}{12}:\dfrac{1}{6}=\dfrac{5}{2}\)

g) \(\left(x\cdot\dfrac{44}{7}+\dfrac{3}{7}\right)\dfrac{11}{5}-\dfrac{3}{7}=-2\)

\(\left(x\cdot\dfrac{44}{7}+\dfrac{3}{7}\right)\cdot\dfrac{11}{5}=-2+\dfrac{3}{7}=-\dfrac{11}{7}\)

\(x\cdot\dfrac{44}{7}+\dfrac{3}{7}=-\dfrac{11}{7}:\dfrac{11}{5}=-\dfrac{5}{7}\)

\(\dfrac{44}{7}x=-\dfrac{5}{7}-\dfrac{3}{7}=-\dfrac{8}{7}\)

\(x=-\dfrac{8}{7}:\dfrac{44}{7}=-\dfrac{2}{11}\)

h) \(\dfrac{13}{4}x+\left(-\dfrac{7}{6}\right)x-\dfrac{5}{3}=\dfrac{5}{12}\)

\(\dfrac{25}{12}x-\dfrac{5}{3}=\dfrac{5}{12}\)

\(\dfrac{25}{12}x=\dfrac{5}{12}+\dfrac{5}{3}=\dfrac{25}{12}\)

\(x=1\)

Mỏi tay woa bn làm nốt nha!!

11 tháng 7 2019

a) (x - 1/2)2 = 4

<=> (x - 1/2)2 = 22

<=> x - 1/2 = -2; 2

<=> x - 1/2 = 2 hoặc x - 1/2 = -2

       x = 2 + 1/2         x = -2 + 1/2

       x = 5/2               x = -3/2

=> x = 5/2 hoặc x = -3/2

b) 10/1/2 - (x + 1/3)2 = 1/1/2

<=> -(x + 1/3)2 = 1/1/2 - 10/1/2

<=> -(x + 1/3)2 = 1/2 - 5

<=> -(x + 1/3)2 = -5.2 + 1/2

<=> -(x + 1/3)2 = -9/2

<=> (x + 1/3)2 = 9/2

<=> x + 1/3 = \(\sqrt{\frac{9}{2}}\)  hoặc x + 1/3 = \(-\sqrt{\frac{9}{2}}\)

       x = \(\frac{3\sqrt{2}}{2}\) - 1/3         x = \(-\frac{3\sqrt{2}}{2}\) -1/3

=> x = \(\frac{3\sqrt{2}}{2}\) - 1/3 hoặc x = \(-\frac{3\sqrt{2}}{2}\) -1/3

c) (x - 1/5)2 + 17/25 = 26/25

<=> (x - 1/5)2 = 26/25 - 17/25

<=> (x - 1/5)2 = (3/5)2

<=> x - 1/5 = -3/5; 3/5

<=> x - 1/5 = 3/5 hoặc x - 1/5 = -3/5

       x = 3/5 + 1/5         x = -3/5 + 1/5

       x = 4/5                  x = -2/5

=> x = 4/5 hoặc x = -2/5