Help rpd plsssssssss

b+t=15 b=15-t
2b+3t=39
2(15-t)+3t=39
30-2t+3t=39
t=39-30=9 triciclete
b=15-t=6 biciclete

[tex]\text{Notam cu a numarul de biciclete si cu b numarul de triciclete.}\\ \text{Obtinem sistemul:}\\ \left \{ {{a+b=15|\cdot 3} \atop {2a+3b=39}} \right. \Leftrightarrow \left \{ {{3a+3b=45} \atop {2a+3b=39}} \right. \\ ~~~~~~~~~~~~~~~~~~~~~~.............. -\\ ~~~~~~~~~~~~~~~~~~~~~~a /=6\\ \text{In total sunt 6 biciclete.} [/tex]