Question 252885
m^2 = 17 means that m = +/- sqrt(17)


(m-1)*(m+1) becomes:


(sqrt(17)-1)*(sqrt(17)+1


or:


(-sqrt(17) - 1) * (-sqrt(17) + 1)


if (sqrt(17)-1)*(sqrt(17)+1, then the product of these 2 factors is processed as follows:


sqrt(17) * sqrt(17) = 17
sqrt(17) * 1 = sqrt(17)
-1 * sqrt(17) = -sqrt(17)
-1 * 1 = -1


add these together to get 17 + sqrt(17) - sqrt(17) - 1 = 17 - 1 = 16


if (-sqrt(17)-1)*(-sqrt(17)+1, then the product of these 2 factors is processed as follows:


-sqrt(17) * -sqrt(17) = 17
-sqrt(17) * 1 = -sqrt(17)
-1 * -sqrt(17) = sqrt(17)
-1 * 1 = -1


add these together to get 17 - sqrt(17) + sqrt(17) - 1 = 17 - 1 = 16


answer would be selection C (16).