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d^2=-81
We move all terms to the left:
d^2-(-81)=0
We add all the numbers together, and all the variables
d^2+81=0
a = 1; b = 0; c = +81;
Δ = b2-4ac
Δ = 02-4·1·81
Δ = -324
Delta is less than zero, so there is no solution for the equation
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