Question

Tìm a , b biết 

\(\frac{a}{27}=\frac{-5}{9}=\frac{-45}{b}\)

Answer 1

\(a=-\frac{5}{9}.27=-15\)

\(b=-45:\left(-\frac{5}{9}\right)=45.\frac{9}{5}=81\)

Đáp số: a=-15; b=81

Answer 2

Bài làm

Ta có: \(\frac{a}{27}=-\frac{5}{9}=-\frac{45}{b}\)

=> a = ( -5 ) . 27 : 9 = - 15

=> b = -45 . 9 : ( - 5 ) = 81

Vậy a = -15; b = 81

Answer 3

=81 nha bạn

Answer 4

A= -15

B=81

Answer 5

\(\frac{a}{27}=\frac{-5}{9}=\frac{-45}{b}\)

\(\Leftrightarrow\hept{\begin{cases}\frac{a}{27}=\frac{-5}{9}\\\frac{-45}{b}=\frac{-5}{9}\end{cases}\Leftrightarrow\hept{\begin{cases}a=27.\left(-5\right):9=-15\\b=-45.9:\left(-5\right)=81\end{cases}}}\)

vậy a=-15 và b=81

Answer 6

Ta có \(\frac{a}{27}=\frac{-5}{9}\Leftrightarrow9a=27.\left(-5\right)\)

                                 \(\Leftrightarrow9a=-135\)

                                 \(\Leftrightarrow a=-15\)

Ta có \(\frac{-5}{9}=\frac{-45}{b}\Leftrightarrow-5=9.\left(-45\right)\)

                                    \(\Leftrightarrow-5b=-405\)

                                    \(\Leftrightarrow b=81\)

Vậy \(\hept{\begin{cases}a=-15\\b=81\end{cases}}\)

Answer 7

\(\frac{a}{27}=\frac{-5}{9}=\frac{-45}{b}\)

* \(\frac{a}{27}=\frac{-5}{9}\)<=> 9a = 27.(-5) <=> 9a = -135 <=> a = -15

* \(\frac{-5}{9}=\frac{-45}{b}\)<=> -5b = 9(-45) <=> -5b = -405 <=> b = 81