Question

Is w^2-9w+81 a trinomial square

Answer 1

no because it would be
if you knew that
ax^2+bx+c was a trinomial square, then the factored form would be

`( √(a)x+ √(c))^(2)` or
`( √(a)x- √(c))^(2)`
so
if w^2-9w+81 is perfect square, factored form is either

`( √(1)x+ √(81))^(2)` or
`( √(1)x- √(81))^(2)` aka
`( x+9)^(2)` or
`( x-9)^(2)`
expand them
(x+9)^2=x^2+18x+81, wron middle term

(x-9)^2=x^2-18x+81 wrong

so it is not