Відповідь:

x = 17/18

Покрокове пояснення:

(10x+1)/10 - 4/15 = 7/9

(3*(10x+1) - (2*4))/30 = 7/9

(3*(10x+1) - (2*4))/30 = 7/9

(30x+3-8)/30 = 7/9

(30x+3-8)/30 - 7/9 = 0

(30x-5)/30 - 7/9 = 0

(3*(30x-5) - (10*7)/90) = 0

(90x - 15 - 70)/90 = 0

(90x-85)/90 = 0

90x - 85 = 0

90x = 85

x = 85/90

x = 17/18