Răspuns:
38. notam t= tata f =fiul
in urma cu 8 ani : t-8=8*(f-8) t= 8f-64+8 t= 8f-56
peste 2 ani: t+2=3*(f+2) t=3f+6-2 t= 3f+4
le egalam 8f-56=3f+4 8f-3f= 56+4 5f=60
f=60:5 fiul=12 ani
t=3*12+4=36+4=40 tata=40 ani
39. b-16=a a-16=b b=2a
a-16=2a-16 2a-a= 16+16 a= 32 b=64
40. a+5 =b-5 b-10=2(a+10) b= 2a+20+10 b=2a+30
b=a+10
a+10= 2a+30 2a-a=30-10 a=40
b=20+10=30 b= 50
41. b-1= 2*(a+1) b= 2a+2+1 b= 2a+3
a-1=b
a-1=2a+3 2a-a= 3+1 a= 4
b=a-1= 4-1=3 b=3
42. b+3=a a+3=4b
b+3+3=4b 4b-b=6 3b=6 b=6:2=3
b=2 a=2+3=5 a=5
