C
the explanation is in the photo
11)
3x = 180
x = 60
12)
6x + 18 = 180
6x = 162
x = 27
<span>a difference of squares
</span>a^2<span> – b^</span>2<span> = (a + b)(a – b)
</span>in this case
<span>(–7x + 4)(–7x – 4)
answer
</span><span>(–7x + 4)(–7x – 4)</span>