Answer:
[tex]x = - \frac{10}{3} [/tex]
alternative forms:
[tex]x = - 3 \frac{1}{3} \: or \: x = - 3.333333333[/tex]
Step-by-step explanation:
[tex]y = 12x + 40 \\ substitute \: y = 0 \\ \\ 0 = 12x + 40 \\ subtract\: 40 \: from \: both \: sides \\ \\ 12x = - 40 \\ divide \: both \: sides \: by \: 12 \\ \\ x = - \frac{10}{3} [/tex]
