standard form for a linear equation means
• all coefficients must be integers, no fractions
• only the constant on the right-hand-side
• all variables on the left-hand-side, sorted
• "x" must not have a negative coefficient
[tex](\stackrel{x_1}{4}~,~\stackrel{y_1}{-1})\hspace{10em} \stackrel{slope}{m} ~=~ 3 \\\\\\ \begin{array}{|c|ll} \cline{1-1} \textit{point-slope form}\\ \cline{1-1} \\ y-y_1=m(x-x_1) \\\\ \cline{1-1} \end{array}\implies y-\stackrel{y_1}{(-1)}=\stackrel{m}{ 3}(x-\stackrel{x_1}{4}) \implies y +1= 3 (x -4) \\\\\\ y+1=3x-12\implies y=3x-13\implies \underline{-3x+y=-13}\implies 3x-y=13[/tex]
now, notice, the equation should have a positivized "x" term, however the material is suggesting "incorrectly" the one that's underlined.
