What is the discriminant of 9x2 + 2 = 10x?
1. –356
2. –172
3. 28
4. 72
I got "28" like this (could you tell me if I'm right?) :
9x^2 -10x + 2 =10x-10x
9x^2 - 10x +2 =0
A=9, B=-10, and C=2
Insert into the equation: x = (-b +/- √b^2 -4ac)/2a
(-(-10) +/- √-10^2 - 4(9)(2))/2(9) (10 +/- √100 - 72)/18
(10 +/- √28)/18 And since the discriminant is just the number under the radical, we don't have to go any further. 28 was the number there... Did I get it right?