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IPMAT/Algebra
Academic discussion and doubt solving for: Progression & Series, Inequalities, Linear Equation, Functions, Modulus, Minima & Maxima, Polynomials, Identities, Indices
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A quadratic polynomial with a leading coefficient of 1 looks like this:
f(x) = (x - a)(x - b) To make this even easier to read, let’s replace those Greek letters with a and b.
We use the clues given in the problem to find the actual numbers for a and b:
From f(0)=p: We find that a×b=p.From f(1)=1/3:
We get the equation (1−a)(1−b)=1/3
The problem says f(x)=0 and f(f(f(f(x))))=0* *share a root.
If we call that root a, then f(a)=0.
Plugging this into the chain:
f(f(f(f(a))))=f(f(f(0)))=f(f(p))=0*.*
For f(f(p)) to be 0, the result of f(p) must be one of our roots (a or b).
By solving (p - a)(p - b) = a along with our other equations, we find:
f(x) = (x - 7/6)(x - 3)
o find f(−3), we just plug in -3 for x:
f(-3) = (-3 - 7/6)(-3 - 3)
f(-3) = (-25/6)(-6)
f(-3) = 25