Question

Two numbers are 10 units away in different directions from their midpoint, m, on a number line. The product of the numbers is –99.
Which equation can be used to find m, the midpoint of the two numbers?

(m – 5)(m + 5) = 99
(m – 10)(m + 10) = 99
m2 – 25 = –99
m2 – 100 = –99

Answer 1

In my opinion the answer is m2 – 100 = –99
proof
m2 – 100 =(m – 10)(m + 10)
for eg. m=1, (-9)(11)= –99

Answer 2

the answer is the option D