Question

i plus u egal cu 31
I<u cu 5
I , u =?

Answer 1

daca i mai mic ca u cu 5 asta imseamna ca u=i-5
inlocuim in ecuatie i+(i-5)=31=>i+i-5=31=>
=>2i=36=> i= 36:2=> i= 18
u= 18-5=> u= 13

Answer 2

i+u=31
i=u+5 \-> u+5+u=31/-5
2u=26/:2
u=13
i=13+5
i=18