Please help (algebra)

Use the quadratic formula to solve the equation. if necessary, round to the nearest hundredth. x^2 - 20 = x a. 5, 4 b. -5, -4 c. -5, 4 d. 5, -4

Me find the value of x each figure.

Right triangle abc has three sides with lengths ab= 119, bc = 169, ca= 120. find the value of cos c. hint: draw and label the triangle. the hypotenuse is always the longest.