In the problem 16-8x=-x², why is the answer 128 in b²-4ac form?
So, I have the equation listed above, and I keep getting 4; which is apparently wrong.
The equation pans out like this;
16-8x=-x²
=x²-8x+16
and then in discriminant form 8²-4(1)(16)... but in the website, it says that the (16) is a (-16) why is this?
Update:I'm a level 1 on Y! Answers, so I can't vote up but thank you SO much Ray!
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I agree with you.
Get it into standard form first:
16 -8x = -x²
x² - 8x + 16= 0 ... confirmed
then a=1, b=-8, c=16
and b² - 4ac = (-8)^2 - 4(1)(16) = 64 - 64 = 0
and x=4 is the sole solution