七年级下数学化简求值练习题七年级下册的比较难一点的“化简求值”题目..最好有答案..

Question

七年级下数学化简求值练习题
七年级下册的比较难一点的“化简求值”题目..最好有答案..

Answer 1

设a>b>0,a^2+b^2=6ab,则(a+b)/(b-a)的值等于?
a^2+b^2=6ab
(a+b)^2=8ab
(a-b)^2=4ab
a>b>0
a+b=√8ab
a-b=√4ab
b-a=-√4ab
(a+b)/(b-a)
=√8ab/-√4ab
=-√2