Question

Which numerical expression equals − 1?

Answer 1

Well to find out if they simplify to -1, work out the expression
A) -1(1-1)
simplify inside the parenthesis
-1(0)
anything times 0 is 0
B) -(-1)(-1)
this one simplifies to -1
C) (− 1) + 1 − 1 (− 1) 
PEMDAS
-1 + -1
2
then work from left to right
-1 + 1 is 0 plus 1 is 1
D)− (− 1) − (− 1)(− 1)
PEMDAS so do Multiplication first
-(-1) is 1 
1 - (-1)(-1)
-1*-1 is 1
1-1 is 0 

The answer to this question is B

Hope this helps :)