help pls. cant figure it out.

[tex]\longrightarrow{\green{a\:=\:2}}[/tex]
[tex]\large\mathfrak{{\pmb{\underline{\purple{Step-by-step\:explanation}}{\purple{:}}}}}[/tex]
➡[tex]\:4a + 1 = a + 7[/tex]
Combining like terms, we have
➡[tex]\:4a - a = 7 - 1[/tex]
➡[tex]\:3a = 6[/tex]
➡[tex]\:a = \frac{6}{3} [/tex]
➡[tex]\:a = 2[/tex]
[tex]\large\mathfrak{{\pmb{\underline{\blue{To\:verify}}{\blue{:}}}}}[/tex]
➪ [tex] \: 4 \times 2 + 1 = 2 + 7[/tex]
➪ [tex] \: 8 + 1 = 9[/tex]
➪ [tex] \: 9 = 9[/tex]
➪ [tex] \: L.H.S.=R. H. S[/tex]
Hence verified.
[tex]\red{\large\qquad \qquad \underline{ \pmb{{ \mathbb{ \maltese \: \: Mystique35}}}}}[/tex]