Question

Calculati 2nr. rationale,a si b, b diferit de 0 stiind ca:
a) a+b=18 si a/b=0.6
b)a/b=0.25 si a+b=16
c)b-a=26 si a/b=1/4
VA ROOG!!

Answer 1

a)a+b=18
a/b=0,6=>a=0,6b inlocuim in prima ecuatie=>o,6b+b=18
6/10b+b=18
3/5b+b=18
3b+5b=90
8b=90/8=45/4
a+45/4=18
4a+45=72
4a=27
a=27/4
b)a/b=0,25 si a+b=16
a=0,25b=1/4b
b/4=b=16
5b=64
b=64/5
a+64/5=16
5a+64=80
5a=16
a=16/5
c)b-a=26 si a/b=1/4
a=b/4
b-b/4=26
3b=104
b=104/3
104/3-a=26
104-3a=78
3a=26
a=26/3