(5(5/9)/2,5)=(x-19)/7(1/5)
2,5×(x-19)=5(5/9)×7(1/5)
2,5×(x-19)=50/9×36/5
2,5×(x-19)=(50×36)/(9×5)
2,5×(x-19)=(5×10×9×4)/(9×5)
2,5×(x-19)=40|:2,5
x-19=40:25/10
x-19=(40×10/25)
x-19=(8×5×2×5)/5×5
x-19=16
x=16+19
x=35
50/9:25/10=16:36/5
50*10/9*25=16*5/36
20/9=80/36
20/9=20/9- истинна.
Ответ: х=35.