已知|2x-3y-5|与√x+y-15互为相反数,求x²+y²的立方根
问题描述：
已知|2x-3y-5|与√x+y-15互为相反数,求x²+y²的立方根
答
已知|2x-3y-5|与√x+y-15互为相反数,
所以 2x-3y-5 =9 得 2x-3y= 14 ①
x+y-15=0 得 2x+2y = 30 ②
② - ①
5y = 16
y = 3.2
x = 15-y = 11.8
求x²+y²的立方根
= (3.2 x 3.2 + 11.8x11.8 )立方根
= 149.48 立方根
= 5.307
答
|2x-3y-5|与√x+y-15互为相反数
2x-3y-5=0且x+y-15=0
联立方程,解得x=10 ,y=5
x²+y²的立方根
=10²+5²立方根
=125立方根
=5