xet phuong trinh bac an x : x^-(m-)*x+m*(m-3)=0 (1)
a) voi gia tri nao cua m thi phuong trinh (1) co 2 nghiem trai dau
b)voi gia tri nao cua m thi phuong trinh (1) co nghiem x1;x2 thoa man he thuc x mot mu 3 x hai mu 3
cho phuong trinh \(x^2-4x+m+1=0\)
a) tim m de phuong trinh co ngiem.
b) tim m de phuong trinh co ngiem \(x_1,x_2\) thoa man:\(x_1^2+x^2_2=10\).
c) tim m de phuong trinh co hai ngiem \(x^2_1,x^2_2\) thoa man:\(x_1^3+x_2^3=34\).
Cho phuong trinh : x2 +( 2m-1 )x +2(m-1) = 0
a) Giai phuong trinh khi m= 2
b) Chung minh phuong trinh co nghiem voi moi m
c) Tim m de phuong trinh co 2 nghiem x1 , x2 thoa man x1 ( x2 - 5 ) + x2 ( x1 - 5 ) = 33
cho phuong trinh 2x2 - mx -20 =0 (tham so m) . a; chung minh rang phuong trinh co hai nghiem trai giau voi moi m .b; tim m phuong trinh co 2 nghiem x1,x2 thoa man 2x1-x2=12
1)Giai phuong trinh:
a) x4+4x2-5=0
b)Cho phuong trinh: x2-2(m+1)x+m2+3m-4=0(1)
Giai phuong trinh khi m=2Chung minh phuong trinh luon co nghiem voi moi m.Goi x1,x2 la nghiem cua phuong trinh,tim m de thoa man dieu kien:x12+x22=10Cho phuong trinh ( an x): x2 -abx+a+b=0 ( voi a,b la 2 so thuc duong ) co 2 nghiem x1,x2. C/m rang : x12+x22\(\ge\) 2(x1+x2 )
giup mk voi, tks nhieu
cho a,b,c la cac so thuc duong thoa man 21ab+2bc+8ac <= 12
khi do gia ti nho nhat cua A=1/a+2/b +3/c
cho a,b la hai so dng thoa man \(a^2+b^3\ge a^3+b^4\) . Chumg minh it nhat 1 trong 2 phuong trinh sau co nghiem
\(ax^2+2x+a=0\)
\(bx^2+2x+b=0\)
1> cho PT : \(x^2-4x+m=0\)
a) Tim m de PT co 2 nghiem phan biet
b) Tim m de phuong trinh co 2 nghiem x1 , x2 thoa man :
\(x1^3+x2^3-5\left(x1^2+x2^2\right)=26\)