Question 917247
An alternative easier proof is to plug x = 2 into the equation and evaluate.



y=-x^3+7x^2-55x+90


y=-(2)^3+7(2)^2-55(2)+90


y=0



Since we get a result of y = 0, this means that x = 2 is indeed a root or zero of y=-x^3+7x^2-55x+90



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Thanks,


Jim