SOLUTION: I have a question that states: find all real zeros of the function: a)f(x)=-7x^4+343x^2 b)f(x)=x^4-16x^2+15 I have no idea how to do these

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: I have a question that states: find all real zeros of the function: a)f(x)=-7x^4+343x^2 b)f(x)=x^4-16x^2+15 I have no idea how to do these      Log On


   



Question 86304: I have a question that states: find all real zeros of the function:
a)f(x)=-7x^4+343x^2
b)f(x)=x^4-16x^2+15
I have no idea how to do these

Answer by scianci(186) About Me  (Show Source):
You can put this solution on YOUR website!
Factor them. For a), take out the GCF of -7x%5E4 and 343x%5E2. Then factor the remaining expression. Set each factor = 0, then solve each one individually. For b), factor x%5E4-16x%5E2+15 as a square trinomial [by reverse FOIL.] Then factor the remaining expression(s) that is/are factorable. Then, as above, set each factor = 0, then solve each one individually.