If a two digit number is 3 times larger than a ten digit number, and the square of the single digit number is equal to the two digit number, find the two digit number. Let the single digit number be x, and the general formula of the equation is______ .

If a two digit number is 3 times larger than a ten digit number, and the square of the single digit number is equal to the two digit number, find the two digit number. Let the single digit number be x, and the general formula of the equation is______ .

Let the ten digits be x, then the single digit be x + 3. According to the meaning of the question, we get (x + 3) 2 = 10x + X + 3, and simplify it to x2-5x + 6 = 0, so the answer is: x2-5x + 6 = 0