maths 20分超急help!!!!help!!!!英英英

Let A be the larger one , B be the smaller one :The difference of two positive integers is 5 :

A - B = 5 .........(1)Two times the square of the smaller one exceeds the square of the larger one by 71 :

2B^2 - A^2 = 71 ..........(2)By (1) , A = B + 5 , sub it to (2) :2B^2 - (B+5)^2 = 712B^2 - B^2 - 10B - 25 = 71B^2 - 10B - 96 = 0(B - 16)(B + 6) = 0B = 16 or B = - 6 (rejected since B is positive)So A = 16+5 = 21The two integers are 21 and 16.

兩個正整數的差係5。兩個較小的數字的二次方比較大的大71
呢題可以用方程式
Let x be the smaller number.
2(x^2)=x+5+71
x^4=x+76
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