help with some math questions?

1. list all possible zeros of the following question:2x^4 - 3x^2 + -4=02. write as a sum of difference of logs of x,y, and zlog(x^5z^3/y^7)3. find the sum of the first 500 terms50,25,12.5,6.25,....4. left f(x)= 1/(x+5) and g(x) = (x +3)^1/2 find the domain of f+g,f-g,fg, and g/f

#1) 2x^4 - 3x^2 + -4=02(x²)² - 3x² -4 = 0Substitute x^2 with q:2q² - 3q - 4 = 0Use quadratic formula (using q instead of x)q = (-(-3)±√((-3)²-4·2·(-4)))/(2·2) = (3 ±√(9+32))/4 = (3 ±√(41))/4Substitute x² for q:x² = (3 ±√(41))/4x = ±√((3 ±√(41))/4)You'll get 2 imaginary answers and 2 real answers.