Complete the Trinomial Product with Mental Multiplication $$( x - 1 ) ( x + 6 ) = x ^ { 2 } + \ldots x - 6$$

Multiple Choice

Complete the trinomial product with mental multiplication. $$( x - 1 ) ( x + 6 ) = x ^ { 2 } + \ldots x - 6$$

A) 4
B) 5
C) 7
D) 2
E) 9