(х - 7/15) / (3/4 - 1/2) = -4,
(х - 7/15) / (3/4 - 2/4) = -4,
(х - 7/15) / (1/4) = -4,
х - 7/15 = -4 * 1/4,
х - 7/15 = -1,
х = -1 + 7/15,
х = -15/15 + 7/15,
х = -8/15
(х - 7/15) / (3/4 - 1/2) = -4,
(х - 7/15) / (3/4 - 2/4) = -4,
(х - 7/15) / (1/4) = -4,
х - 7/15 = -4 * 1/4,
х - 7/15 = -1,
х = -1 + 7/15,
х = -15/15 + 7/15,
х = -8/15