Question

Stiind ce 7stilouri si 6 pixuri costa 235 lei , iar 2 stilouri si 3 pixuri costa 80 lei , determinati pretul unui pix si pretul unui stilou ,

Answer 1

7a+6b=235
2a+3b=80 Ix 2
7a+6b=235
4a+6b=160
--------------------
3a-------=75
a=75:3
a=25 lei costa un stilou
25x2+3b=80
3b=80-50
b=30:3
b=10 lei costa un pix

Answer 2

7s+6p=235
2s+3p=80
3p=80-2s
7s+3p+3p=235
7s+2x3p=235
7s+2(80-2s)=235
7s+160-4s=235
3s=75
s=75:3=25lei costa un stilou
2x25+3p=80
50+3p=80
3p=80-50=30
p=30:3=10 lei costa un pix