a)  2 x (-7 + 4) = 2 x -7 + 2 x 4 = __ + __ = __

-6 is the final answer but I don't think -3 + -3 is what the problem is looking for.  It seems to me that they want to know if you remember the correct order of operations in math.

Let's look at the problem step by step:

2 x (-7 + 4)

The first thing in the order of operations is to do anything that is inside parentheses.  So, first you do the addition:

2 x (-3)

-6

OK, now for the second part.  When there are no parentheses, you have to do multiplication or division first.

2 x -7 + 2 x 4

-14 + 8

I think the -14 + 8 is what is supposed to go in the blanks, with the final answer, of course, being -6.

b)  7 x (X + 3) = (7 x __) + (__ x 3)

Since we can't simplify X + 3 inside the parentheses, the next step is to multiply 7 by the two parts -- first by X and then by 3.

(7 x X) + (7 x 3)

So, the first blank is filled by X and the second is filled by 7.