If it has infinite solutions
[tex]\boxed{\sf \dfrac{a_1}{a_2}=\dfrac{b_1}{b_2}=\dfrac{c_1}{c_2}}[/tex]
[tex]\\ \sf\longmapsto \dfrac{2}{p+q}=\dfrac{3}{p+q-3}[/tex]
[tex]\\ \sf\longmapsto 2(p+q-3)=3(p+q)[/tex]
[tex]\\ \sf\longmapsto 2p+2q-6=3p+3q[/tex]
[tex]\\ \sf\longmapsto 2p-3p+2q-3q=6[/tex]
[tex]\\ \sf\longmapsto -p-q=6[/tex]
[tex]\\ \sf\longmapsto p+q=-6[/tex]
[tex]\\ \sf\longmapsto p=-6-q[/tex]
Take p as 1
