Question

The sum of two digits of a number is 7. if 9 is subtracted from the number, the digits are reversed. find the number.​

Answer 1

Answer:

43

Step-by-step explanation:

Let the no is xy

then x+y=7(given)

then , x=7-y----------(1)

given that 9 is subtracted from the number

I.e., 10x+y-9

(don't get confused here , the no. is taken as 10x+y that is equal to xy because for example let a no. be 67 then here digits are 6 and 7 like x and y their sum is x+y=6+7=13, but =>10x +y =(10×6)+7=67, hope you can understand what I want to tell you from this)

after subtracting 9 from the number the digits are reversed I.e.,

=>10x+y-9=10y+x (xy---->yx see above explanation)

putting the value of x from equation 1 in this we get,

=>10(7-y)+y-9=10y+(7-y)

70-10y+y-9=10y+7-y

70-9y-9=9y+7

70-9y-9-7=9y

54-9y=9y

54=18y

y=54/18=3

therefore x = 7-y=7-3=4

Hence the number is 43(x=4,y=3)

please mark as brainliest answer , thankyou....