Question

daca a/b=3/5 calculeaza 2a-3b/5a-b

Ajutor , dau coroana si puncte

Answer 1

$\frac{a}{b} = \frac{3}{5} = > a = \frac{3b}{5}$

$\frac{2a - 3b}{5a - b} = \frac{2 \times \frac{3b}{5} - 3b}{5 \times \frac{3b}{5} - b} = \frac{ \frac{6b}{5} - 3b }{ \frac{15b}{5} - b} = \frac{ \frac{6b}{5} - \frac{15b}{5} }{3b - b}$

$= \frac{ - \frac{9b}{5} }{2b} = - \frac{9b}{5} \times \frac{1}{2b} = - \frac{9b}{10b} = - \frac{9}{10}$

Answer 2

a / b = 3 / 5 ⇒   5 a = 3 b

( 2 a - 3 b ) / ( 5 a - b ) = ( 2 a - 5 a ) / ( 5 a - 5 a / 3 ) =

= - 3 a / ( 15 a / 3 - 5 a / 3 ) =

=  - 3 a :  10 a / 3 =

= - 3 a × 3 / 10 a =

= - 9 / 10