要用方程
1 there is a double-digit number.The figure on its single is 1 larger than that on its tenth-digit ,and the double digit numbei is 5 times as large as the sum of figures on its tenth-digit and on its single-digit.Question:what is the double-digit number?2 there is a double-digit number.The figure on its tenth-digit is 1 smaller than that on its single digit.If the figures on its tenth-digit and on its single-digit are exchand,the newly-got number will be 9 larger than the original one.Question::what is the original double-digit?