Question

a two digit number is such that the product of its digit is 8. whwn 18 is added to the number, the digit interchange their place. determine the number​

Answer 1

Let the digits be X and Y

Now according to the question X × Y=8_____(1)

And 10X + Y + 18 = 10Y + X

9X + 18 = 9Y

X + 2 = Y

Putting Y in (1)

X² + 2X = 8

X² + 2X - 8 = 0

Upon solving the quadratic equation

X = -4,2

X = 2 (X can't be negative)

Y = 2 + 2 = 4