Which of the following is not a perfect square. A. x^2+4x+16 B. x^2+6x+9 C. 4x^2+4x+1 D. 1-2x+x^2 E. 9x^2-6x+1
Let us consider the general form of a quadratic equation.
`ax^2+bx+c = 0`
When we have a perfect square that means we have the following combination.
`b^2-4ac = 0`
`b^2-4ac = 16-4xx1xx16 = -48`
`b^2-4ac = 6^2-4xx1xx9 = 0`
`b^2-4ac = 16-4xx4xx1 = 0 `
`b^2-4ac = (-2)^2-4xx1xx1 = 0 `
`b^2-4ac = (-6)^2-4xx9xx1 = 0`
So the answer is A.