cacy zadania w zalacznikach :)
zad.1 a) 2x + y = 7 x + 2y = 6,50 zad. 2 a) x + 4y = 0 2x + 3y = 25 x = -4y 2x + 3y = 25 x = -4y 2 * (-4y) + 3y = 25 x = -4y -8y + 3y = 25 x = -4y -5y = 25 / : (-5) x = -4y y = -5 x = -4 * (-5) = 20 y = -5 x = 20 y = -5 b) 3m + n = 9 2m - 5n = -11 n = 9 - 3m 2m - 5 * (9 - 3m) = -11 n = 9 - 3m 2m - 45 + 15 = -11 n = 9 - 3m 2m = -11 + 45 - 15 n = 9 - 3m 2m = 19 / :2 n = 9 - 3m m = 9,5 n = 9 - 3 * 9,5 = - 19,5 m = 9,5 n = -19,5 m = 9,5 zad.3 a) 2x + 5y = 7 3x - 5y = 3 ___________________ 2x + 3x = 7 + 3 5x = 10 / : 5 x = 2 2x + 5y = 7 2 * 2 + 5y = 7 4 + 5y = 7 5y = 7 - 4 5y = 3 / :5 y = 3/5 b) 5x + 3y = 0 -x - 2y = 7 / * 5 5x + 3y = 0 -5x - 10y = 35 _____________________ 3y - 10y = 35 -7y = 35 / : (-7) y = -5 5x + 3y = 0 5x + 3 * (-5) 5x = -15 / : (-5) x = -3