Notice that this expression is a difference: this less that. We MUST perform the two products BEFORE subtracting the 2nd from the first.
(-6i)(-7-6i) becomes 42i + 36i^2, or 42i -36
-(7i)(3-2i) becomes -[21i - 14i^2], or -[21i + 14]
Combine these two products.
42i-21i -36 -14
21i - 50 (answer)