# How do you determine whether #4x^2-3x+9# is a perfect square trinomial?

##### 1 Answer

Jul 2, 2017

#### Explanation:

Let us discuss the identity

Observe the RHS. While

#a^2# is the square of the first term#a# #b^2# is the square of the second term#b# - sign of
#a^2# and#b^2# is same and is positive #2ab# is twice the product of two terms#a# and#b# and its sign is#+# or#-# depending on its sign in#(a+-b)^2#

In

but (leaving the sign) middle term is **not**

Hence,