week7:relation between roots and coefficients of quadratic equations.

The topic at the page number 131 of the recomended book of Doleiani MP, Wooton W, Becknback EF, Sharron S, "Algcbra and rignometry 1978, Houghuon and Mifrilin.Kaufimann JE. Coliege Algebra and trigonometry, 1978, PWS-Kent Company, Boston. dition), 1986, PWS-Kent Compahy, Boston. Hogg, R. M. & Craig, A. T. "Introduction to Mathematical Statistics