Question

A two digit number is such that the product of its digits is 8.When 18 is subtracted from the number ,the digits are reserved .find the number.

Answer 1

the number is 24

Let the ten's and unit digit be x and 8/x respectively.
Then,(10x +8/x)+ 18 = 10 x8/x+ x
 10x2 + 8 + 18x = 80 + x2
 9x2 + 18x - 72 = 0
 x2 + 2x - 8 = 0
 (x + 4)(x - 2) = 0
 x = 2.

Answer 2

let no be 10y+x
part 1= xy=8     therefore y=8/x
part 2 -
10y+x-18=10x+y
=9(y-x)=18
=y-x=2
=8/x-x=2
xsq.+2x-8=0
sove it . u will get the value of x and y