If the equation (m ^ 2-1) x ^ 2 - (m-1) x + (2m + 1) Y-3 = 0 is a bivariate linear equation, then the value of M is (if the equation is a univariate linear equation, then the value of M is?

If the equation (m ^ 2-1) x ^ 2 - (m-1) x + (2m + 1) Y-3 = 0 is a bivariate linear equation, then the value of M is (if the equation is a univariate linear equation, then the value of M is?

The quadratic equation of two variables requires the coefficient of quadratic term to be 0, and the coefficients of X and y cannot be 0
m²-1=0
M = 1 or - 1
When m = 1, the coefficient of X is 0
So m = - 1
For the equation of one variable, the coefficient of quadratic term is 0, and one of X and Y coefficients is 0
When m = 1, X coefficient is 0, y coefficient is not 0
So the quadratic equation of two variables, M = - 1
Equation of first degree with one variable, M = 1