Question

Afla a si b daca a supra b este ehivalenta cu 2pe 7 si b minus a egal 20

Answer 1

a/b=2/7 => 7*a=2*b

b-a=20 => 2*b-2*a=40
                 7*a-2*a=40  =>5*a=40  => a=40/5=8
                                                            b-a=20 =>b=20+a=20+8 =>b=28                                      

Answer 2

a/b=2/7
b-a=20
a/b=2/7 ⇒7a=2b ⇒a=2/7xb
b- 2/7 xb=20
aducem la acelasi numitor
7b-2b=140
5b=140
b=28
28-a=20
a=8