Using the Multiplication Property of - 1

a. - (a + 5)

b. - (-x + 31)

c. - (4x - 12)

A. - (a+5)

Because the negative sign is outside the parenthesis, multiplying by - 1 just removes the negative sign:

- (a+5) * - 1 = a+5

B. - (-x+31)

Apply the distributive property:

- (-x+31) becomes ( - - x + 31) which simplifies to (x+31)

multiply that by - 1 to get - x+31

C. - (4x+12)

Because the negative sign is outside the parenthesis, multiplying by - 1 just removes the negative sign:

- (4x+12) * - 1 = 4x+12