5 (a - 1) - 15 = 3 (a + 2) + 4
[tex] \sf \dashrightarrow \: 5 (a - 1) - 15 = 3 (a + 2) + 4 [/tex]
[tex]\sf \dashrightarrow \: 5 \times a - 5 \times 1 - 15 = 3 \times a + 3 \times 2 + 4 [/tex]
[tex]\sf \dashrightarrow \: 5 a - 5 - 15 = 3 a + 6 + 4 [/tex]
[tex]\sf\dashrightarrow \: 5 a - 20 = 3 a + 10 [/tex]
[tex]\sf\dashrightarrow \: 5 a - 20 - 3a - 10 = 0 [/tex]
[tex]\sf\dashrightarrow \: 2 a - 30 = 0 [/tex]
[tex]\sf\dashrightarrow \: 2 a = 30[/tex]
[tex]\sf\dashrightarrow \: a = \cancel\dfrac{30}{2} [/tex]
[tex]\sf\dashrightarrow \: a = 15[/tex]
[tex] \Large \underline{\boxed{\tt{a = 15 }}}[/tex]
