[tex]a)[/tex]
[tex](x - y = 5 \\ (y = 3 - x [/tex]
[tex](x - y = 5 \\ (x + y = 3[/tex]
[tex]2x = 8[/tex]
[tex]x = 4[/tex]
[tex]4 + y = 3[/tex]
[tex]y = - 1[/tex]
[tex]b)[/tex]
[tex](4x - y = 6 \\ (5x - 2y = 6[/tex]
[tex](y = - 6 + 4x \\ (5x - 2y = 6[/tex]
[tex]5x - 2( - 6 + 4x) = 6[/tex]
[tex]x = 2[/tex]
[tex]y = - 6 + 4 \times 2[/tex]
[tex]y = 2[/tex]