The mathematician was born in 1936 and passed away at the age of 35 in 1971, as calculated from the given equation.
Given that the mathematician stated 'in the year extit{x}, I had the square root of extit{x} years,' we can set up the equation extit{birth year} + extit{x} = ( extit{birth year} + extit{x})^(1/2) to find the birth year. Solving this, the birth year is extbf{1936}.
If the mathematician died in 1971, their age at death would be 1971 - birth year = 1971 - 1936 = 35 years. Therefore, they were extbf{35 years old} when they passed away.
https://brainly.com/question/36423375