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Please show the steps to this word problem 10 points for best answer?
The units digit of the two digit number is one less then the square of the 10 digit. The number with the digits reversed is seven more than twice the original number. Find the original number
2 Answers
- MechEng2030Lv 77 years agoFavorite Answer
Let the original 2 digit number be xy. From the information given in the problem:
y = x^2 - 1
When digits are reversed:
10y + x = 2(10x + y) + 7
10(x^2 - 1) + x = 2(10x + x^2 - 1) + 7
10x^2 + x - 10 = 2x^2 + 20x + 5
8x^2 - 19x - 15 = 0
x = (19 +/- √(361 - 4(8)(-15))/16 = 3 and y = 3^2 - 1 = 8
So original number was 38.
- Anonymous7 years ago
Mmhmm^