If f(x)=x4−10x2+9f(x) = x^4 - 10x^2 + 9f(x)=x4−10x2+9, factor completely and find all real roots.
x=pm1,pm3x = \\pm 1, \\pm 3x=pm1,pm3
x=pm9,pm1x = \\pm 9, \\pm 1x=pm9,pm1
x=1,3x = 1, 3x=1,3 only
x=pmsqrt5x = \\pm \\sqrt{5}x=pmsqrt5 only