Solving a quadratic equation

I can not factor or group this to set it equal to zero to determine the solution. Can you help me? 4x^4-65x^2+16=0

past exam paper

Please help. I am having trouble with this paper and i have exam on friday! --- (See attached file for full problem description)

degrees and angles

for the given triangle, side a =7.0, side b= 4.0 and side c = 6.0 what is the size in degrees of the angle b( the angle opposite side b)?

rectangular coordinates

find the rectangular cordinates of the point (r,degrees)= (-5,-52 degrees)

past exam paper

Please help me with a couple of questions on a past exam paper see attachment.