Subtract the [tex]x^2[/tex] terms from each other, then the [tex]x[/tex] terms, then the ones without any [tex]x[/tex] whatsoever.
[tex](12x^2 - 8x + 12) - (9x^2 +22x-46)[/tex]
First, we'll subtract [tex]9x^2[/tex] from [tex]12x^2[/tex]
[tex]12x^2-9x^2- = 3x^2[/tex]
Result: [tex]3x^2[/tex]
Next, we'll subtract [tex]22x[/tex] from [tex]-8x[/tex]
[tex]-8x - 22x = -30x[/tex]
Result: [tex]-30x[/tex]
Finally, we'll subtract [tex]-46[/tex] from [tex]12[/tex]
[tex]12-(-46) = 12+46 = 58[/tex]
Result: [tex]58[/tex]
Now, we can add these 3 results together.
First, we had [tex]3x^2[/tex], then [tex]-30x[/tex], and finally [tex]58[/tex].
Thus, our subtraction of
[tex](12x^2 - 8x + 12) - (9x^2 +22x-46)[/tex]
equals
[tex]3x^2-30x+58[/tex]