F5 Maths 07

odd number=單數，i.e.1,3,5,7,9,11。。。，所以每一個連接的單數是相差2


when x is the larger number, the smaller number will be (x-2)

1)sum of the square of two odd numbers= x^2+(x-2)^2

2)four times of the product=4·x·(x-2)

∵1)<2), i.e. x^2+(x-2)^2＜4·x·(x-2)

∴1)=2)-2, and x^2+(x-2)^2=4·x·(x-2)-2
therefore,the answer is D

the larger odd number = x
the smaller odd number = x - 2
first number is less than the second number by 4
first number = sum of square of 2 odd numbers = x^2 + (x-2)^2
4times of second number = 4 x product of 2 odd numbers = 4x(x-2)
x^2 + (x-2)^2 = 4x(x-2) - 4
(ans: D)