\[(5a + 1)(2a - 3) =\]
\[= (10a - 3)(a + 1)\]
\[10a^{2} - 15a + 2a - 3 =\]
\[= 10a^{2} + 10a - 3a - 3\]
\[10a^{2} - 13a - 3 - 10a^{2} - 7a + 3 = 0\]
\[- 20a = 0\]
\[a = 0.\]