Question

4a+9b/5a-b, если 3а+5b=0

Answer 1

4a+9b/5a-b, если 3а+5b=0 3a=-5b

3а=-5b b/a=-3/5 b=-3a/5

4a+(9/5)(-3/5)-b=
=4a-27/25+3a/5=
=-27/25+(20a+3a)/5=
=23a/5-27/25

Answer 2

4a+9b/5a-b, если 3а+5b=0 a=-5b/3
(4(-5b/3)+9b)/(5(-5b/3)-b)=((-20b+27b)/3)/(-25b-3b/3)=7b/3:(-28b/3)=7b/3*(-3/28b)=-1/4