X^2-Y^2 =40......(i) and X+Y=10, solve this simultaneously please?
回答 (5)
2016-11-21 10:31 pm
✔ 最佳答案
x^2 - y^2 = 40factor
(x - y)(x+y) = 40
x+y = 10
substitute
10(x-y) = 40
x-y = 4
now you have two linear equations.
x+y = 10
x = 7
y = 3
2016-11-19 10:50 pm
x^2 - (10 - x)^2 = 40
x^2 - (100 - 20x + x^2) = 40
x^2 - 100 + 20x - x^2 = 40
-100 + 20x = 40
I assume you can solve that linear equation.
x^2 - (100 - 20x + x^2) = 40
x^2 - 100 + 20x - x^2 = 40
-100 + 20x = 40
I assume you can solve that linear equation.
2016-11-20 10:55 pm
x=10-y
(10-y)^2-y^2=40
100-20y+y^2-y^2-40=0
-20y+60 =0 devide by 2
-10y=-30 then y=-30/-10 =3
x=10-3=7
(10-y)^2-y^2=40
100-20y+y^2-y^2-40=0
-20y+60 =0 devide by 2
-10y=-30 then y=-30/-10 =3
x=10-3=7
2016-11-20 12:01 am
X = 7, Y = 3
2016-11-19 11:49 pm
x+y = 10
y=10-x
x^2-y^2 = 40
x^2 - (10-x)^2 = 40
x^2 -(100-20x+x^2) = 40
x^2 -100 +20x -x^2 = 40
20x-100 = 40
20x =140
x= 7
y=10-x=10-7 = 3
x=7
y=3
y=10-x
x^2-y^2 = 40
x^2 - (10-x)^2 = 40
x^2 -(100-20x+x^2) = 40
x^2 -100 +20x -x^2 = 40
20x-100 = 40
20x =140
x= 7
y=10-x=10-7 = 3
x=7
y=3
收錄日期: 2021-04-23 23:59:41
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20161119144412AANtB3o