Question

calculati nr nat de doua cifre de forma ab pentru care:ab=5×a+3×b

Answer 1

ab=10a+b
10a+b=5a+3b
5a=2b
a=2
b=5

nr este 25

Answer 2

$ab=10a+b \\ ab=5a+3b \\ 10a+b=5a+3b \\ 10a-5a=3b-b \\ 5a=2b \\ a=2 \\ b=5 \\ ab=10*2+5 \\ ab=20+5 \\ ab=25$