What is the sum of all possible values of $x$ such that $2x(x-10)=-50$?
First, multiply it out. 2x2 – 20x = –50
Add 50 to both sides 2x2 – 20x + 50 = 0
We don't have to, but let's
divide both sides by 2 x2 – 10x + 25 = 0
Factor the quadratic (x – 5)(x – 5) = 0
The only value is x = 5
Or if your class counts both roots, even though they're the same, then it's 10.
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