\(\frac{9}{12}\)\(+\frac{4}{7}\)\(=\frac{9:3}{12:3}\)\(+\frac{4}{7}\)\(=\frac{3}{4}\)\(+\frac{4}{7}\)\(=\frac{3\times7}{4\times7}\)+ \(\frac{4\times4}{7\times4}\)= \(\frac{21}{28}\)+ \(\frac{16}{28}\)=\(\frac{21+16}{28}\)=\(\frac{37}{28}\)

 9/12+4/7=37/28

ĐKXĐ:...

Để gõ công thức cho nhanh ta đặt \(\left\{{}\begin{matrix}\sqrt{x}=a\\\sqrt{y}=b\end{matrix}\right.\)

\(\frac{a^2+b^2}{a+b}:\left(\frac{a^2+b^2}{ab}+\frac{b^2}{a^2-ab}-\frac{a^2}{b^2+ab}\right)=\frac{a^2+b^2}{ab}:\left(\frac{a^2+b^2}{ab}+\frac{b^2}{a\left(a-b\right)}-\frac{a^2}{b\left(a+b\right)}\right)\)

\(=\frac{a^2+b^2}{ab}:\left(\frac{\left(a^2+b^2\right)\left(a^2-b^2\right)+b^3\left(a+b\right)-a^3\left(a-b\right)}{ab\left(a-b\right)\left(a+b\right)}\right)\)

\(=\frac{a^2+b^2}{ab}:\left(\frac{a^4-b^4+ab^3+b^4-a^4+a^3b}{ab\left(a-b\right)\left(a+b\right)}\right)\)

\(=\frac{a^2+b^2}{ab}:\left(\frac{ab\left(a^2+b^2\right)}{ab\left(a-b\right)\left(a+b\right)}\right)=\frac{\left(a^2+b^2\right)\left(a-b\right)\left(a+b\right)}{a^2+b^2}=a^2-b^2=x-y\)

3 phan 2

12 phan 4 bang 3

9 phan 7

tk nha

\(\frac{9}{6}=\frac{9\div3}{6\div3}=\frac{3}{2}\)

\(\frac{12}{4}=\frac{12:4}{4:4}=\frac{3}{1}=3\)

\(\frac{90}{70}=\frac{90:10}{70:10}=\frac{9}{7}\)

rút gọn bằng cách chia nha

k mik nha bn

9 phần 6 = 3 phan 2

12 phần 4 =3

90 phần 70= 9 phần 7

tk cho minh nha 

chuc ban hoc gioi

\(C=1+2^2+2^4+...+2^{2008}\)

\(\Rightarrow4C=2^2+2^4+...+2^{2010}\)

\(\Rightarrow4C-C=\left(2^2+2^4+...+2^{2010}\right)-\left(1+2^2+2^4+...+2^{2008}\right)\)

\(3C=2^{2010}-1\)

\(C=\frac{2^{2010}-1}{3}\)

\(C=1+2^2+2^4+....+2^{2008}\)

\(\Rightarrow4C=2^2+2^4+.....+2^{2010}\)

\(\Rightarrow3C=4C-C=\left(2^2+2^4+...+2^{2010}\right)-\left(1+2^2+.....+2^{2008}\right)\)

\(\Rightarrow3C=2^{2010}-1\)

\(\Rightarrow C=\frac{2^{2010}-1}{3}\)

C=1+22+24+...+22008

⇒4C=22+24+...+22010

⇒4C−C=(22+24+...+22010)−(1+22+24+...+22008)

3C=22010−1

C=22010−13 

Phân số tối giản là: 5/7, 23/24

Phân số rút gọn là: 6/9, 12/24, 6/14

6/9=2/3   12/24=1/2   6/14=3/7

Phân số tối giản là \(\frac{5}{7};\frac{23}{24}\)

Phân số rút gọn được là \(\frac{6}{9};\frac{12}{24};\frac{6}{14}\)

Rút gọn \(\frac{6}{9}=\frac{2}{3};\frac{12}{24}=\frac{1}{2};\frac{6}{14}=\frac{3}{7}\)

15/24 = 5/8 ; 21/24 = 7/8 ; 54/18 = 9/3 ; 100/25 = 4/1.

15/24=5/8;21/42=1/2;54/18=3/1;100/25=4/1

15/24 = 5/8

21/42 = 7/8

54/18 = 3/1 = 3

100/25 = 4/1 = 4

= \(\frac{662}{611}\).

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Ai tk cho mình mình tk lại.

662/661 nha ban k mik

662/611

4/12=1/3

chia cho 4

ai mk mk lại

\(\frac{4}{12}\)= \(\frac{1}{3}\)nha bạn

Bằng \(\frac{1}{3}\)nhé !