Question

3. How many solutions does the system of equations have? 2x=-10y+ 6 and x+5y=3

1. One
2. Two
3. Infinitely many
4. None

Answer 1

3. Infinitely many

Explanation:

`\left\{\begin{array}{ccc}ax+by=c\\dx+ey=f\end{array}\right\\\\(1)\\\text{if}\ a=d,\ b=e,\ c=f,\ \text{then the system of equations has infinitely many solutions}\\Example:\\\left\{\begin{array}{ccc}2x-3y=5\\2x-3y=5\end{array}\right\\(2)\\\text{if}\ a=d,\ b=e,\ c\\eq f,\ \text{then the system of equations has no solution}\\Example:\\\left\{\begin{array}{ccc}2x-3y=5\\2x-3y=-5\end{array}\right`

`(3)\\\text{if}\ a\\eq d\ \text{or}\ b\\eq e,\ \text{then the system of equations has infinitely many solutions}\\Example:\\\left\{\begin{array}{ccc}x-3y=5\\2x-3y=5\end{array}\right`

`\text{We have:}\\\\\left\{\begin{array}{ccc}2x=-10y+6&\text{add 10y to both sides}\\x+5y=3\end{array}\right\\\left\{\begin{array}{ccc}2x+10y=6&\text{divide both sides by 2}\\x+5y=3\end{array}\right\\\left\{\begin{array}{ccc}x+5y=3\\x+5y=3\end{array}\right`