SOLUTION: Hello, could you please help me with this problem: A cubic polynomial f(x) has leading coefficient -2 and intercepts the y-axis at 2. if f(1)=1, and f(-2)=-2, find f(-1) and write

Algebra ->  Test -> SOLUTION: Hello, could you please help me with this problem: A cubic polynomial f(x) has leading coefficient -2 and intercepts the y-axis at 2. if f(1)=1, and f(-2)=-2, find f(-1) and write       Log On


   

Question 1016425: Hello, could you please help me with this problem: A cubic polynomial f(x) has leading coefficient -2 and intercepts the y-axis at 2. if f(1)=1, and f(-2)=-2, find f(-1) and write the complete function.
Answer by josgarithmetic(39616) About Me  (Show Source):
You can put this solution on YOUR website!
f%28x%29=-2x%5E3%2Bbx%5E2%2Bcx%2Bk.

-2%2A0%5E3%2Bb%2A0%5E2%2Bc%2A0%2Bk=2 meaning that k=2.
Revising f gives f%28x%29=-2x%5E3%2Bbx%5E2%2Bcx%2B2, and you can form your other two equations to solve them as a system for b and c.

Hopefully you can do that.