Определите при каком значении числа а уравнение 6x + 5 = a -2 и 3 x - 7 = 4 а -1 равносильно​

6x + 5 = a – 2 ⇔ 3x – 7 = 4а – 1

6x = a – 2 – 5 ⇔ 3x = 4a – 1 + 7

6x = a – 7 ⇔ 3x = 4a + 6

x = (a – 7) / 6 ⇔ x = (4a + 6) / 3

(a – 7) / 6 = (4a + 6) / 3

a – 7 = 8a + 12

7a = –7 – 12

a = –19/7