Question

初三数学~~求详细过程!

1.化简求值.
(1){(4b√a/b)+(2/b√ab^3)} (b>0)
(2)若x=√2+1,y=√2-1,求x^2+xy+y^2的值
2.已知a-b=√12,ab=1,b>0,求a+b值
3.已知x^2+(1/x^2)=14,且x>1,求(x^2+1)/x和(x^2-1)/x的值

Answer 1

(4b√a/b)+(2/b√ab^3) (b>0)
=4√ab+2√ab=6√ab

x^2+xy+y^2=（x+y)^2=(2√2)^2=8
(a-b)^2+4ab=12+4=16

{(x^2+1)/x}^2=x^2+(1/x^2)+2=16 (x^2+1)/x=4

[(x^2-1)/x]^2=x^2+(1/x^2)-2=12
(x^2-1)/x=√12

Answer 2

打勾是什么意思？你说清楚，我马上给答案

Answer 3

1.(4b√a/b)+(2/b√ab^3)=(4√ab)+(2a√ab)=(4+2a)√ab
2.x^2+xy+y^2=(x+y)^2-xy=8-1=7
3.(a+b)^2=(a-b)^2+4ab=12+4=16
4.(x+1/x)^2=x^2+2+1/(x^2)=16 得出(x^2+1)/x=4
同理:(x^2-1)/x=2√3