Ta co \(x^2+4x+5=\left(x^2+4x+4\right)+1\)\(=\left(x+2\right)^2+1\)
Ma \(\left(x+2\right)^2\ge0\forall x\) Nen \(\left(x+2\right)^2+1>0\)
Vay da thuc tren khong co nghiem
a) Xac dinh he so m de da thuc A(x) = mx2_2x co nghiem la 3
b) Chung to da thuc sau khong co nghiem
B(x) = x2+4x+10
Giup tui voi
Chung to rang da thuc sau khong co nghiem
B(x)=x^2+x+1
Cho da thuc P(x)=2(x-3)2 +5
Chung minh rang da thuc da thuc da cho khong co nghiem
Chung to da thuc sau khong co nghiem:
a, x2 + x + 2
b, x4 + 3x2 + 5
cho da thuc f(x) =-6x^3 + 8x^2 -1/2 -4^4 va g(x) = 4x^4+5/2-5x^2+6x^3
tinh h(x)=f(x)+g(x)
chung to h(x) khong co nghiem
cho da thuc f(x) voi cac he so nguyen thoa man f(3)-f(4)=5. chung minh f(x)-6 khong co nghiem nguyen
Chung minh da thuc Q(x) = x^4 + 3x^2 + 1 khong co nghiem voi moi gia tri cua x
cho da thuc p(x) thoa man : (x-2)p(x+5)=(x2-9)p(x+2). chung minh rang p co it nhat 3 nghiem
cho bieu thuc 4x. Hay ly luan de chung to bieu thuc do khong co gia tri lon nhat khong co gia tri nho nhat