Question

Este de clasa a 5-a dar nu am stiut cum sa pun

Answer 1

a.a+b=31.5
a=8b
8b+b=31.5
9b=31.5
b=3.5
a=8*3.5
a=28

b.a+b=51.66
a:b=7.5=>a=7.5b
7.5b+b=51.66
8.5b=51.66
b=6.07
a=7.5*6.07=45.58

c.a-b=30.8
b=a/12
a-a/12=30.8
Inmultim cu 12
12a-a=369.6
11a=369.6
a=33.6
b=33.6/12=2.8

d.a*b=40
a=2.5b
2.5b*b=40
2.5b**2=40
b**2=16
b=+-radical din 16 
b1=+4
b2=-4
a1=2.5*4=10
a2=2.4*(-4)=-10

e.a*b=80
b=a/3.2
a*a/3.2=80
a**2/3.2=80
a**2=80*3.2
a**2=256
a=+-radical din 256
a1=16
a2=-16
b1=16/3.2=5
b2=16/(-3.2)=-5