a) x-14=3x + 18

x - 3x = 18 + 14

-2x = 32

=> x = -16

b) (x+7)(x-9)=0

=> TH1: x+7=0 => x = -7

=> TH2: x-9=0 => x = 9

c) x(x+3) =0

=> TH1: x=0

=> TH2: x+3 =0 => x = -3

d) (x-2)(5-x)=0

=> TH1: x-2=0 => x=2

=> Th2: 5-x=0 => x=5 

1+1=2

2+2=4

3+3=6

4+4=8

5+5=10

6+6=12

7+7=14

8+8=16

9+9=18

x=2

X=4

X=6

X=8

X=10

X=12

X=14

X=16

X=18

1+1 = 2

2+2 = 4

3+3 = 6

4+4 = 8

5+5 = 10

6+6 = 12

7+7 = 14

8+8 = 16

9+9 = 18

k mk nha

Bài 1: tính: a) 8 và 5/9 : 5 và 1/2 b) 7 và 3/4 - 2 và 1/8 c) 1 và 3/4 x 2 và 5/6 d) 7 - 2 và 2/3 e) 2 và 3/7 x 1 và 3/4 g) 5 và 1/3 : 3 và 1/5 Bài 2: tìm X: X : 3 và 1/3= 2 và 2/5 + 7/10 Và là biểu thị cho hỗn số nhé

Bài 1:

a, 85995​:51221​

= 779977​: 112211​

= 779977​ x 211112​

= 149914​
 

b, 73443​ - 21881​

= 314431​ - 178817​

= 458845​

c, 13443​ x 25665​

= 7447​ x 176617​

= 1192424119​
 

d, 7 - 22332​

= 213321​ - 8338​

= 133313​
 

e, 23773​ x 1

a)\(3\frac{2}{5}.2\frac{1}{7}=\frac{17}{5}.\frac{15}{7}=\frac{51}{7}\)

b) \(8\frac{1}{6}:2\frac{1}{2}=\frac{49}{6}:\frac{5}{2}=\frac{49}{6}.\frac{2}{5}=\frac{49}{15}\)

a  17/5*21/7=457/35

b 49/6:21/2=88/126

Chuyển các hỗn số thành p/s rồi thực hiện phép tính (theo mẫu):

a) \(3\frac{2}{5}\times2\frac{1}{7}=\frac{17}{5}\times\frac{15}{7}=\frac{51}{7}\)

b) \(8\frac{1}{6}\div2\frac{1}{2}=\frac{49}{6}\div\frac{5}{2}=\frac{49}{6}\times\frac{2}{5}=\frac{49}{15}\)

a) \(x\cdot3\dfrac{1}{4}+\left(-\dfrac{7}{6}\right)\cdot x-1\dfrac{2}{3}=\dfrac{5}{12}\)

\(\Rightarrow\dfrac{3}{4}x-\dfrac{7}{6}x-\dfrac{2}{3}=\dfrac{5}{12}\)

\(\Leftrightarrow9x-14x-8=5\)

\(\Leftrightarrow-5x-8=5\)

\(\Leftrightarrow-5x=5+8\)

\(\Leftrightarrow-5x=13\)

\(\Rightarrow x=-\dfrac{13}{5}\)

Vậy \(x=-\dfrac{13}{5}\)

b) \(5\dfrac{8}{17}:x+\left|2x-\dfrac{3}{4}\right|=-\dfrac{7}{4}\)

\(\Rightarrow5\dfrac{8}{17}:x+\left|2x-\dfrac{3}{4}\right|=-\dfrac{7}{4}\left(đk:x\ne0\right)\)

\(\Leftrightarrow\dfrac{93}{17}\cdot\dfrac{1}{x}+\left|2x-\dfrac{3}{4}\right|=-\dfrac{7}{4}\)

\(\Leftrightarrow\dfrac{93}{17x}+\left|2x-\dfrac{3}{4}\right|=-\dfrac{7}{4}\)

\(\Leftrightarrow\left[{}\begin{matrix}\dfrac{93}{17x}+2x-\dfrac{3}{4}=-\dfrac{7}{4}\left(đk:2x-\dfrac{3}{4}\ge0\right)\\\dfrac{93}{17x}-\left(2x-\dfrac{3}{4}\right)=-\dfrac{7}{4}\left(đk:2x-\dfrac{3}{4}< 0\right)\end{matrix}\right.\)

đến đây bạn giải tiếp nhé

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

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

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

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

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

Vậy \(x_1=-\dfrac{1}{2};x_2=\dfrac{1}{3}\)

a, \(\dfrac{4x}{7}=\dfrac{1}{5}+\dfrac{2}{3}=\dfrac{3+10}{15}=\dfrac{13}{15}\Rightarrow60x=91\Leftrightarrow x=\dfrac{91}{60}\)

b, \(\dfrac{5}{7}:x=\dfrac{1}{6}+\dfrac{4}{5}=\dfrac{5+24}{30}=\dfrac{29}{30}\Leftrightarrow x=\dfrac{5}{7}:\dfrac{29}{30}=\dfrac{150}{203}\)

a) 2/3 x + 1/2 = 1/10

2/3 x = 1/10 - 1/2

2/3 x = -2/5

x = -2/5 : 2/3

x = -3/5

b) 2/3 x + 1/5 = 7/10

2/3 x = 7/10 - 1/5

2/3 x = 1/2

x = 1/2 : 2/3

x = 3/4

c) (3 4/5 - 2x) . 1 1/3 = 5

19/5 - 2x = 5 : 4/3

19/5 - 2x = 15/4

2x = 19/5 - 15/4

2x = 1/20

x = 1/20 : 2

x = 1/40

d) x/7 = 6/(-21)

x = 6.7/(-21)

x = -2

=1,4 x\(\dfrac{15}{49}-\) \(\left(\dfrac{4}{5}+\dfrac{2}{3}\right)\) : 2\(\dfrac{1}{5}\)

=  \(\dfrac{3}{7}\) - \(\dfrac{22}{15}\) : \(\dfrac{11}{5}\)

= \(\dfrac{3}{7}\) -  \(\dfrac{2}{3}\)

= \(-\dfrac{5}{21}\) 

( 2\(\dfrac{1}{5}\) + \(\dfrac{3}{5}\) \(\times\) \(x\)) = \(\dfrac{3}{4}\)

  \(\dfrac{11}{5}\) + \(\dfrac{3}{5}\)\(x\) = \(\dfrac{3}{4}\)

            \(\dfrac{3}{5}\)\(x\) = \(\dfrac{3}{4}\) - \(\dfrac{11}{5}\)

           \(\dfrac{3}{5}\)\(x\) = - \(\dfrac{29}{20}\)

             \(x\) = -\(\dfrac{29}{12}\)

3\(\dfrac{1}{3}\) x \(x+16\)\(\dfrac{3}{4}\)= 13,25

\(\dfrac{10}{3}\) x \(x\) + \(\dfrac{67}{4}\) = 13,25

\(\dfrac{10}{3}\) x \(x\) = 13,25 - \(\dfrac{67}{4}\)

\(\dfrac{10}{3}\times x=\) \(\dfrac{103}{28}\) 

          \(x\) = \(\dfrac{103}{28}:\dfrac{10}{3}\)

          \(x=\) \(\dfrac{309}{280}\)