Hg/9h^-2g^-6 how to do it

Cos^2x+cos^2(120°+x)+cos^2(120°-x)i need this asap. pls me

The construction of copying qpr is started below. the next step is to set the width of the compass to the length of ab. how does this step ensure that a new angle will be congruent to the original angle? by using compass take the measures of angle and draw the same arc according to it.

Which shows one way to determine the facts of x3+4x2+5x+20 by grouping