X^4-30x^2+125=0 solve the equation by making an approproate substitution

Use sigma notation to represent the following series for 9 terms.

I’m still confused on how to work the percentages

White shapes and black shapes are used in a game. some of the shapes are circles. while the rest are squares. the ratio of the number of white shapes to the number of black shapes is 5: 11. the ratio of the number of white cicrles to the number of white squares is 3: 7. the ratio of the number of black circles to the number of black squres is 3: 8. work out what fraction of all the shapes are circles.