In the two-digit number ,the units digit is greater than the ten digit by 3 , and the sum of the squares of the two digits is greater than the two-digit number by 3. Let the units digit be x.
a) Express, in terms of x,
(i) the ten digit,
(ii) the value of two-digit number.
b) Hence find the two-digit number.
Maths (quadratic equation )
2008-10-01 4:28 am
回答 (1)
2008-10-01 5:04 am
✔ 最佳答案
a) i) x-3ii) (x-3)(10)+x
b) (x-3)2+x2-3=(x-3)(10)+x
x2-6x+9+x2-3=10x-30+x
2x2-17x+36=0
(2x-9)(x-4)=0
x=9/2 ,4
Because 9/2 is a fraction and can't be a digit. So x is equal to 4.
The no. = (4-3)(10)+4
=14
參考: me
收錄日期: 2021-04-24 08:24:27
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