Question

Help when you can:)
Which of the following constants can be added to x^2 - 3x to form a perfect square trinomial?
A. 1 1/2
B. 2 1/4
C. 4 1/2

Answer 1

(ax+b)^2 = (ax)^2 + 2abx + b^2
in our case
a = 1
2ab = -3
so
2b = -3 (Cause a=1)
so
b=-3/2

so b^2 = 9/4 which is 2 1/4.

Answer 2

Thank you so much! @Coolsector