Question 1147780
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<pre>

It is clear from the condition that c= 10, d= -18  and  e= f(0) = 9.


So, the polynomial is  f(x) = ax^4 + bx^3 + 10x^2 - 18x + 9.


Now, substitute x= 1 into the last expression for the polynomial and take into account that x= 1 is the root.


You will get
   

    f(1) = a + b + 10 - 18 + 9 = 0,


which implies


    a + b = -10 + 18 - 9 = -1.    <U>ANSWER</U>
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Solved.