Question

[Nguyễn Mai Kiên Nhân]

Cho a+8/b+9 = a-8/b-9 (a khác 8, b khác 9), hãy tìm a/b. Mình đang cần gấp

Answer 1

[Capheny Bản Quyền]

\(\frac{a+8}{b+9}=\frac{a-8}{b-9}\)   

\(\left(a+8\right)\left(b-9\right)=\left(a-8\right)\left(b+9\right)\)   

\(ab-9a+8b-72=ab+9a-8b-72\)   

\(-9a+8b=9a-8b\)  

\(8b+8b=9a+9a\)   

\(16b=18a\)   

\(b=\frac{18a}{16}\)   

\(b=\frac{9}{8}a\)   

\(\frac{b}{a}=\frac{9}{8}\)   

\(\frac{a}{b}=\frac{8}{9}\)

Answer 2

[Gukmin]

Có:\(\frac{a+8}{b+9}=\frac{a-8}{b-9}\)\(\left(a\ne8;b\ne9\right)\)

\(\Leftrightarrow\left(a+8\right)\left(b-9\right)=\left(a-8\right)\left(b+9\right)\)

\(\Leftrightarrow ab-9a+8b-72=ab+9a-8b-72\)

\(\Leftrightarrow-9a+8b=9a-8b\)

\(\Leftrightarrow18a=16b\)

\(\Leftrightarrow\frac{a}{b}=\frac{8}{9}\)

Vậy\(\frac{a}{b}=\frac{8}{9}\)

Linz