Question

Va rog ex 14 si 15!!

Answer 1

14.

a. n(5/8) + 2(n/8) = 6

=> 8n+5/8 + 16+n/8 =6

=> 9n+21/8=6     I x8

=>9n+21 = 48     I -21

=>9n=27             I :9

=> n=3

b.6n+5/6 + 18+n/6 = 5

=>23+7n/6=5     I x6

=>23+7n =30     I -23

=>7n=7               I :7

=>n=1

c.20+n/4 + 4n+3/4=7

=>23+5n=7          I x4

=> 23+5n=28      I -23

=>5n=5                I :5

=>n=1

15.ba/a = 4a+b/a      I x a

=> ba=4a+b

=> ba = 10b + a

=>10b+a = 4a+b     I-a-b

=>9b=3a                I:3

=>3b=a

a = 1,2,3

=> b=3,6,9

=> nr. ba=31,62,93