Prosta ma ogólny wzór: f(x)=ax+b
[tex]\left \{ {{5=-3a+b} \atop {-2=7a+b}} \right.\\ \left \{ {{5=-3a+b} \atop {2=-7a-b}} \right.\\\\ 7=-10a\\\\ a=-\frac{7}{10}\\\\ 5=-3*(-\frac{7}{10})+b\\\\ 5=\frac{21}{10}+b\\\\ b=5-\frac{21}{10}\\\\ b=\frac{50}{10}-\frac{21}{10}\\\\ b=\frac{29}{10}\\\\ \left \{ {{a=-\frac{7}{10}} \atop {b=2\frac{9}{10}} \right. \\\\\\ y=-\frac{7}{10}x+2\frac{9}{10}[/tex]
Pozdrawiam :)