SOLUTION: How do you solve (d+2)(d-5)=-6 if it is a polynomial equation?

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Question 118310: How do you solve (d+2)(d-5)=-6 if it is a polynomial equation?
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
%28d%2B2%29%28d-5%29=-6 Start with the given equation


d%5E2-3d-10=-6 Foil


d%5E2-3d-10%2B6=0 Add 6 to both sides


d%5E2-3d-4=0 Combine like terms

%28d-4%29%28d%2B1%29=0 Factor the left side (note: if you need help with factoring, check out this solver)



Now set each factor equal to zero:
d-4=0 or d%2B1=0

d=4 or d=-1 Now solve for d in each case


So our answer is
d=4 or d=-1




Check:
Let's check the first solution d=4
%28d%2B2%29%28d-5%29=-6 Start with the given equation


%284%2B2%29%284-5%29=-6 Plug in the first solution d=4


%286%29%28-1%29=-6 Combine like terms


-6=-6 Multiply. Since the two sides of the equation are equal, this verifies our answer.


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Now let's check the second solution d=-1
%28d%2B2%29%28d-5%29=-6 Start with the given equation


%28-1%2B2%29%28-1-5%29=-6 Plug in the second solution d=-1


%281%29%28-6%29=-6 Combine like terms


-6=-6 Multiply. Since the two sides of the equation are equal, this verifies our answer.


So both of our answers have been verified.