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f(x) = x^4 - x^3 - 4^x2 +4 
 
By DesCartes' rule of signs it has 2 sign changes so it
has 2 or 0 positive real zeros.
We know by the factored form 
f(x) = (x^3 - 4x - 4)(x-1)
That it has at least 1 positive real zero, 1, so by DesCartes' 
rule of signs, it MUST have 2 positive real zeros. 
We know since 1 has multiplicity 1 that the curve cuts
through the x-axis there.
We know it goes up on the far right because the leading
coefficient 1 of 1x^4 is positive.  We know that it also goes 
up on the far left also because the degree 4 is even.
We make a table of 5 values:
 x | y
-2 | 12
-1 | 2
 0 | 4
 2 |-4
 3 |22 
We plot those points:
 So the graph must look something like this:
So the graph must look something like this:
 Edwin
Edwin