Question

求解，快

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Answer 1

1)2x^2+3x-1=0
x1+x2=-3/2,x1x2=-1/2
2)2m^2-2m-1=0,2n^2-2n-1=0,
所以m,n是方程2x^2-2x-1=0,的两个根
m+n=1,mn=-1/2
m^2n+mn^2=mn(m+n)=-1/2*1=-1/2
3)p^2=3p+2,............(1)
2q^2=3q+1...............(2)
(1)-(2)*2得
p^2-4q^2=3p-6q
(p-2q)(p+2q)-3(p-2q)=0
(p-2q)(p+2q-3)=0
因p-2q不等于0
所以有p+2q-3=0
p+2q=3
(1)+(2)*2得
p^2+4q^2=3(p+2q)+4=3*3+4=13
所以,p^2+4q^2=13