SOLUTION: Please help me, i need to know how to solve this for a test tommorow! What are the zeros of f(x)=-3(x-2)^2 + 5

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Please help me, i need to know how to solve this for a test tommorow! What are the zeros of f(x)=-3(x-2)^2 + 5       Log On


   

Question 123798: Please help me, i need to know how to solve this for a test tommorow!
What are the zeros of f(x)=-3(x-2)^2 + 5

Answer by rapaljer(4671) About Me  (Show Source):
You can put this solution on YOUR website!
A zero means to let f(x) = 0 and solve for x:

f(x)=-3(x-2)^2 + 5 =0
Subtract 5 from each side:
-3%28x-2%29%5E2++=-+5

Divide by -3:
+%28x-2%29%5E2=5%2F3
Take the squsre root of each side:
x-2=0%2B-sqrt%285%2F3%29

Add 2 to each side:
x=2%2B-sqrt%285%2F3%29+

There are other ways to write this, by rationalizing the denominator:
x=2%2B-+sqrt%28%285%2F3%29%2A%283%2F3%29%29

x=2%2B-+sqrt%2815%2F9%29
x=2%2B-+%28sqrt%2815%29%29%2F3

You may need to express this with a common denominator:
+x=%286%2B-sqrt%2815%29%29%2F3

R^2