(6x + 9) · 8 - 4 = 164 как решается? срочно плиз​

(6x + 9) · 8 - 4 = 164

(6x + 9) · 8 = 164 + 4

(6x + 9) · 8 = 168

6x + 9 = 168 : 8

6x + 9 = 21

6x = 21 - 9

6x = 12

x = 12 : 6

x = 6

6