PLS HELP ME I BEG YOU
Pleaseee help me solve this sistem of equations with stepss

Logan wants to know how many skateboards have defective parts. he inspects 20,000 skateboards and keeps track of the number of defects per board. use his probability distribution table to find the expected value for defects on a skateboard.

Ten times the square of a non-zero number is eqaul to ninety times the number

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