SOLUTION: Help! I need help with a couple of problems. 1. Solve the inequality. Give the solution set in interval notation and graph it. x^2-2x-3>0 - 2.Find the real nu

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Help! I need help with a couple of problems. 1. Solve the inequality. Give the solution set in interval notation and graph it. x^2-2x-3>0 - 2.Find the real nu      Log On


   

Question 110036: Help! I need help with a couple of problems.
1. Solve the inequality. Give the solution set in interval notation and graph it. x^2-2x-3>0
-

2.Find the real number c such that x^2-2/3x+c is a perfect square trinomial.
Answer by edjones(8007) About Me  (Show Source):
You can put this solution on YOUR website!
x^2-2x-3>0
(x-3)(x+1)>0
x>3, x>-1
graph%28500%2C500%2C-10%2C10%2C-10%2C10%2Cx%5E2-2x-3%29
X(-infinity,-1)U(3,infinity)
.
x^2-2/3x+c
to find c in all problems of this type, divide b by 2 and square the result.
-2/3*1/2=-1/3
(-1/3)^2=1/9 Ans.
Check:
x^2-2/3x+1/9=(x-1/3)^2
.
Ed