[tex]\\ \rm\longmapsto 5x-y[/tex]
[tex]\\ \rm\longmapsto 5(7)-12[/tex]
[tex]\\ \rm\longmapsto 35-12[/tex]
[tex]\\ \rm\longmapsto 23[/tex]
Answer:
[tex]5x - y \\ x = 7 \\ y = 12 \\ then \: 5x - y = 5 \times 7 - 12 \\ = 35 - 12 \\ = 23 \\ thank \: you[/tex]