Question 490883
Let 
f= father’s current age
s=son’s current age

the sum of ages of the son and his father is 69. 

f+s=69
s=69-f………….(1)

son's age increased by 9 = s+9

Father 's age is twice as his son's age increased by 9 means
f=2(s+9)
f=2s+18…………(2)

Put the value of s from (1) to  (2)
f=2(69-f)+18
f=138-2f+18
f=-2f+156
f+2f=156
3f=156
f=156/3
f=52

Put the value of f in (1)
s=69-f
s=69-52
s=17

Father is 52 and Son is 17 years old at present.