d) \(x+\dfrac{3}{4}=\dfrac{36}{144}.\dfrac{-12}{9}\)

\(\Rightarrow x+\dfrac{3}{4}=\dfrac{-1}{3}\)

\(\Rightarrow x=\dfrac{-1}{3}-\dfrac{3}{4}\)

\(\Rightarrow x=\dfrac{-4}{12}-\dfrac{9}{12}\)

\(\Rightarrow x=\dfrac{-13}{12}\)

e)

\(\dfrac{8}{23}.\dfrac{46}{24}=\dfrac{1}{3}.x\)

\(\Rightarrow\dfrac{1}{3}.x=\dfrac{2}{3}\)

\(\Rightarrow x=\dfrac{2}{3}:\dfrac{1}{3}\)

\(\Rightarrow x=\dfrac{2}{3}.3\)

\(\Rightarrow x=2\)

f)

\(\dfrac{1}{5}:x=\dfrac{1}{5}-\dfrac{1}{7}\)

\(\dfrac{1}{5}:x=\dfrac{7}{35}-\dfrac{5}{35}\)

\(\dfrac{1}{5}:x=\dfrac{2}{35}\)

\(\Rightarrow x=\dfrac{1}{5}:\dfrac{2}{35}\)

\(\Rightarrow x=\dfrac{1}{5}.\dfrac{35}{2}\)

\(\Rightarrow x=\dfrac{7}{2}\)

f) 1/5 : x = 1/5 - 1/7

1/5 : x = 2/35

x = 1/5 : 2/35

x = 7/2

e) x + 3/4 = 36/144 . -12/9

x + 3/4 = -1/3

x = -1/3 - 3/4

x = -13/12

d, x+3/4=-1/3

=>x=-13/12

e, 2/3=1/3.x

=>x=2

f, 1/5:x=2/35

=>x=1/5:2/35

=>x=7/2

g: \(\Leftrightarrow\left(x-\dfrac{1}{2}\right)^2=\dfrac{4}{9}-\dfrac{1}{3}=\dfrac{1}{9}\)

=>x-1/2=1/3 hoặc x-1/2=-1/3

=>x=5/6 hoặc x=-1/6

h: \(\Leftrightarrow x\cdot\dfrac{16}{5}-\dfrac{22}{15}:\dfrac{11}{3}=\dfrac{7}{20}\)

\(\Leftrightarrow x\cdot\dfrac{16}{5}=\dfrac{7}{20}+\dfrac{22}{15}\cdot\dfrac{3}{11}=\dfrac{7}{20}+\dfrac{2}{5}=\dfrac{3}{4}\)

hay x=15/64

i: \(\Leftrightarrow\left(\dfrac{9}{2}-2x\right)=\dfrac{13}{2}:\dfrac{65}{61}=\dfrac{61}{10}\)

=>2x=-8/5

hay x=-4/5

a: \(=\dfrac{2}{7}\cdot\dfrac{-3}{4}\cdot\dfrac{4}{7}=\dfrac{-6}{49}\)

b: \(=\dfrac{3}{5}:\dfrac{1}{15}=\dfrac{3}{5}\cdot15=9\)

c: \(=\dfrac{41}{7}-3-\dfrac{1}{2}=\dfrac{33}{14}\)

d: \(=-\dfrac{25}{12}-\dfrac{23}{12}-\dfrac{3}{2}=-4-\dfrac{3}{2}=-\dfrac{11}{2}\)

okoko

Ừ , xét số dư cho 3 

TRẢ LỜI:

Đáp án: C

Trong hiện tượng giao thoa sóng trên mặt nước, khoảng cách giữa hai cực đại liên tiếp nằm trên đường nối tâm hai sóng có độ dài là một nửa bước sóng.

thi tự làm nhé bạn

Câu 1:

\(a,\text{Slt: }\widehat{A_4}\text{ và }\widehat{B_1}\\ \text{Đv: }\widehat{A_4}\text{ và }\widehat{B_3}\\ b,a\text{//}b\Rightarrow\left\{{}\begin{matrix}\widehat{A_4}=\widehat{B_1}=42^0\left(\text{so le trong}\right)\\\widehat{B_2}=180^0-\widehat{A_4}=138^0\left(\text{trong cùng phía}\right)\end{matrix}\right.\)

Chết anh nhầm!!!

Anh làm 1 câu thôi nhá, sắp thi anh rồi ;-;

x = 5/4 - 2/3

x = 7/12

a) 5/4 - x = 2/3

             x = 5/4 - 2/3

             x = 7/12

b) X : 2/5 + 3/10 = 5

    X : 2/5 = 5 - 3/10

    X : 2/5 = 47/10

    X         = 47/10 x 2/5

    X         = 47/25

112-45+5x=87
45+5x=112-87
5x=25-45
x=-25:5
x=_5

\(\sqrt{4x^2-4x+9}=3\\ \Rightarrow4x^2-4x+9=9\\ \Rightarrow4x\left(x-1\right)=0\\ \Rightarrow\left[{}\begin{matrix}4x=0\\x-1=0\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=0\\x=1\end{matrix}\right.\)

Ta có: \(\sqrt{4x^2-4x+9}=3\)

\(\Leftrightarrow4x^2-4x=0\)

\(\Leftrightarrow4x\left(x-1\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=1\end{matrix}\right.\)

Bài 5: B (vì 11,605 <11,615)

Bài 9: \(Y:3,75=13,25+1,75\)

⇒ \(Y:3,75=15\)

⇒ \(Y=15:3,75\)

⇒ \(Y=4\)

bài 5: B            

bài 8: 

a. 252,32           b. 3,1

c. 19,17             d. 397,925

bài 9:

 Y : 3,75 = 13,25 + 1,75

 Y : 3,75 = 15

     Y = 15 x 3,75

     Y = 56,25