- Thread starter
- #1
- Feb 5, 2012
- 1,621
srirahulan's question titled "Algeb" from Math Help Forum,
Let \(\alpha\mbox{ and }\beta\) be the two roots of these quadratic equations. Then, according to the first equation,
\[\alpha+\beta=-\frac{2}{a}~~~~~~(1)\]
Considering the second equation,
\[\alpha+\beta=-2~~~~~~~(2)\]
By (1) and (2);
\[-\frac{2}{a}=-2\]
\[\therefore a=1\]
Hi srirahulan,If \(ax^2+2x+1=0\mbox{ and }x^2+2x+a=0\) have the common roots, find the real value of a.
Let \(\alpha\mbox{ and }\beta\) be the two roots of these quadratic equations. Then, according to the first equation,
\[\alpha+\beta=-\frac{2}{a}~~~~~~(1)\]
Considering the second equation,
\[\alpha+\beta=-2~~~~~~~(2)\]
By (1) and (2);
\[-\frac{2}{a}=-2\]
\[\therefore a=1\]