Question

допоможіть! будь ласка 30 б​

Answer 1

$\displaystyle 5x^4-x^2-4=0\\5t^2-t-4=0\\\\t=-\frac{4}{5},t=1\\ \\x^2=-\frac{4}{5},x^2=1\\ \\x \notin R, x=-1,x=1\\x=б1$