Question 1030951
Let x be in ten's place
and y in unit's place

the number is 10x+y

10x+y = (x+y) *7 +3
10x+y = 7x+7v+3

3x-6y = 3
/3
x-2y=1.........................(1)

Digits interchanged , number will be 10y+x

10y+x = 8(x-y)+1
10y+x=8x-8y+1
18y-7x=1.........................(2)

Multiply (1) by 7 and add it to (2)
7x-14y=7
18y-7x=1

4y=8
y=2

Now x-2y=1

plug y

x-4=1
x=5

The number is 52