Answer:
[tex]\boxed{3)}[/tex]
Step-by-step explanation:
A difference of squares has the form (a - b)(a + b)
Your expression is (-5x - 3)(-5x + ?
Let's compare this with your expression.
[tex]\begin{array}{cclccl}(a & - & b) & (a & + & b)\\\downarrow & & \downarrow & \downarrow & & \downarrow \\(-5x & - & 3) & (-5x & + & \mathbf{3)} \\\end{array}\\\\\text{The missing term is }\boxed{\mathbf{3)}}[/tex]