Question

Answer 1

Giúp em ạ 

 

Answer 2

Câu 1:

\(A=\left(-5;0\right);B=\)\([-4;5)\)

\(A\cap B=\)\([-4;0)\)

\(A\cup B=\left(-5;5\right)\)

\(A\B=\left(-5;-4\right)\)

\(A\B=\)\([0;5)\)

Answer 3

Câu 2:

Theo giả thiết ta có HPT:

\(\left\{{}\begin{matrix}-1=9a+3b+c\\-\dfrac{b}{2a}=3\\0=a+b+c\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}c-9a=-1\\-6a=b\\c-5a=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}a=\dfrac{1}{4}\\b=-\dfrac{3}{2}\\c=\dfrac{5}{4}\end{matrix}\right.\)

Vậy \(y=\dfrac{1}{4}x^2-\dfrac{3}{2}x+\dfrac{5}{4}\)