Solve for k
k=-8
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256-4\times 2\left(40+k\right)=0
Calculate 16 to the power of 2 and get 256.
256-8\left(40+k\right)=0
Multiply 4 and 2 to get 8.
256-320-8k=0
Use the distributive property to multiply -8 by 40+k.
-64-8k=0
Subtract 320 from 256 to get -64.
-8k=64
Add 64 to both sides. Anything plus zero gives itself.
k=\frac{64}{-8}
Divide both sides by -8.
k=-8
Divide 64 by -8 to get -8.
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