Man these ppl who keep deleting my questions are mad annoying

Which statement is true about a number and its additive inverse? a. their product is always one. b. their sum is always one. c. they are always reciprocals of each other. d. their sum is always zero.

What is the common difference for this arithmetic sequence? -6,-2,2,6,10 a.4 b.5 c.3 d.6

X^2/100+y^2/25=1 the length of the major axis is: a)5 b)10 c)20