✔ 最佳答案
(1)
/ x^2+xy=2-----(1)
\ y-3x=7---------(2)
From (2)
y=3x+7----------(3)
Sub(3)into(1)
x^2+x(3x+7)=2
x^2+3x^2+7x-2=0
(4x-1)(x+2)=0
x=1/4 or x=-2
if x=1/4, y=31/4
if x=-2, y=1
(2)由題目中,我們可知
/ x^2+y^2=169--------(1)
\ x+y=17----------------(2)
from (2)
y=17-x-----(3)
sub(3)into(1)
x^2+(17-x)^2=169
2x^2-34x+120=0
x^2-17x+60=0
(x-12)(x-5)=0
x=12 or x=5
if x=5, y=12
if x=12, y=5