Question

Which of the following is a perfect square trinomial?

x2 - 5x + 6
x² – 3x+4
x2 + 20x + 100
x2 + 14x - 49

Answer 1

`x^2-5x+6\\(x-3)(x-2)`

`x^2-3x+4\\(x-4)(x+1)`

`x^2+20x+100\\(x+10)(x+10)\\(x+10)^2`

That's the answer

`x^2+14x-49\\x(x+14)-49`

Only
`x^2+20x+100` is a perfect square trinomial