Given that the mean of a sample m, 4,2,5,3 is n, and M + n = 4, then the variance of the sample is () solve equations 1 + 2 of X + 1 = 2x + 2 of X

Given that the mean of a sample m, 4,2,5,3 is n, and M + n = 4, then the variance of the sample is () solve equations 1 + 2 of X + 1 = 2x + 2 of X

The variance is 2
To solve the equation, you multiply (x + 1) (x -)
In this way, it becomes a linear equation of one variable, which is easy to solve
Don't forget to verify it in the end
If = 0 in the value of X (x + 1) (x-1) is an increasing root, it must be rounded off
So this equation has no solution
If it is not equal to 0, the value obtained is the solution of the original equation
Almost all fractional equations are solved in this way