tolong jawab nomor 20 pakai cara.bsk dikumpulin di guru les tolong saya

[tex]\frac{y - y1}{y2 - y1} = \frac{x - x1 }{x2 - x1} \\ \frac{y - ( - 6)}{ - 7 - ( - 6)} = \frac{x - 8}{3 - 8} \\ \frac{y + 6}{ - 7 + 6} = \frac{x - 8}{3 - 8} \\ \frac{y + 6}{ - 1} = \frac{x - 8}{ - 5} \\ - 5(y + 6) = - 1(x - 8) \\ - 5y - 30 = - x + 8 \\ - 5y = - x + 8 + 30 \\ - 5y = - x + 38 \\ y = ( - x + 38) \div ( - 5) \\ y = \frac{1}{5} x - \frac{38}{5} [/tex]
[tex] m1 = m2\\ m2 = \frac{1}{5} [/tex]
[tex]y - y1 = m(x - x1) \\ y - 3 = \frac{1}{5} (x - ( - 6)) \\ y - 3 = \frac{1}{5} (x + 6) \\ y - 3 = \frac{1}{5} x + \frac{6}{5} \\ y = \frac{1}{5} x + \frac{6}{5} + 3 \\ y = \frac{1}{5} x + \frac{6}{5} + \frac{15}{5} \\ y = \frac{1}{5} x + \frac{21}{5} \\ 5y = x + 21 \\ 5y - x = 21[/tex]
jawaban = A