a. Xac dinh a de nghiem cua da thuc f(x) = 2x-4 cung la nghiem cua da thuc g(x) = x^2 - ax +2b.
b. Cho f(x) = ax^3 + bx^2 + cx + d, trong do a; b; c; d la hang so va thoa man : b = 3a + c
Chung to rang : f(1) = f(-2)
cho hai da thuc sau:
f(x) = ( x-1) ( x+2) g(x) = x3 + ax2 +bx +2 A) tim nghiem cua f(x) B) xac dinh a va b biet nghiem cua da thuc f(x) cung la nghiem cua da thuc g(x)
a,tim a biet da thuc A(x)=ax2- 1/2x +1 co 1 nghiem la -1/2
b, tim a,b cua da thuc :B(x)= ax2+bx+5 biet B(1)=6 va B(-2) = 15
c, cho da thuc C(x)= ax+b .Tim a,b biet :
x=4 la nhgiem cua C(x)va C(2)=1
cho cac da thuc f(x)=ax+b va g(x)=bx+a trong do a;b khac 0 biet rang nghiem cua da thuc f(x) la so duong cmr nghiem cua da thuc g(x) cung la 1 so duong
Bai2: Cho da thuc f(x)=x\(^2\)+4x-5
a, So -5 co phai la nghiem cua f(x) ko?
bViet tap hop S tat ca cac nghiem cua f(x)
Bai 3; Thu gon roi tim nghiem cua cac da thuc sau
a, f(x)=x(1-2x)+(2x\(^2\)-x+4)
b,g(x)=x(x-5)-x(x+2)+7x
c, h(x)=x(x-1)+1
moi nguoi xin hay giup to
Cho 2 da thuc A= 2x^3 + x^2 - 4x +x^3 + 3 ; B= 6x + 3x^3 -2x + x^2 - 5
a, Tinh tong hai da thuc A+B
b, Tinh hieu hai da thuc A-B
c, tim nghiem cua da thuc hieu A - B vua tim duoc o y b.
Cau 1; cho\(\frac{x}{2}=\frac{y}{5}\)vaxy=90. So cap (x;y) thoa man la
Cau 2 : Cho a+d=b+c va \(a^2+d^2=b^2+c^2\)(b,d khac 0).Khi do 4 so lap thanh ti le thuc nao
Cau 3 :GTLN cua phan so \(\frac{7n-8}{2n-3}\)
Cau 4: Cho A=\(\frac{12}{x-15}\) dieu kien de 0<A<1 va A>1
Cau 5 ; tim x biet /-x-5//x=5=10
Cau 6: tap hop cac so nguyen cua x thoa man (3x^2-51)^2014=(-24)^2014
Cau 7: tap hop cac so thoa man /x-y/+/y+9/25/=0
Bai 4: Xac dinh he so m de cac da thuc sau nhan 1 lam nghiem
a,mx\(^2\)+2x+8 b, 7x\(^2\)+mx-1 c, x\(^5\)-3x\(^2\)+m
Bai5: Cho da thuc f(x)=x\(^2\)+mx +2
a, Xac dinh m de f(x) nhan -2 lam 1 nghiem
b, Tim tap hop cac nghiem cua f(x) ung voi gia tri vua tim duoc cua m
Bai 6: Tim da thuc f(X) roi tim nghien cua f(x) biet
\(x^3+2x^2\left(4y-1\right)-4xy^2-9y^3-f\left(x\right)=-5x^3+8x^2y-4xy^2-9y^3\)
cho x,y,z la 3 so thuc tuy y thoa man x+y+z=0 va -1< x<1,-1<y<1,-1<z<1.chung minh rang da thuc x^2+y^4+z^6 co gia tri khong lon hon 2