Question

câu 3b ạ

 

Answer 1

Bài 3:

\(b,\text{PT hoành độ giao điểm }\left(d_1\right);\left(d_2\right):\\ \dfrac{1}{4}x-6=5+3x\Leftrightarrow\dfrac{11}{4}x=-11\Leftrightarrow x=-4\Leftrightarrow y=-7\Leftrightarrow A\left(-4;-7\right)\\ \Leftrightarrow A\left(-4;-7\right)\in\left(d_3\right)\Leftrightarrow\left\{{}\begin{matrix}a=2\\-4a+b=-7\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}a=2\\b=1\end{matrix}\right.\)