Question

Which of the following is a perfect-square
trinomial?
A. x² - 10x + 20
B. 4x² - 2x + 4
C. x² - 14x + 49
D. x² - 10x + 100

Answer 1

C. x² - 14x + 49

Explanation:

Because x² - 14x + 49= (x-7)²

Answer 2

A trinomial expression can be called as a perfect square if it is of the form $ax^{2} +bx+c$

now, if we go through the given equations ,

equation $x^{2} -14x+49$ satisfies the condition .

ALSO $x^{2} -14x+49$  can be expressed as $(x-7)^{2}$

i.e if we multiply the binomial $(x-7)$ with $(x-7)$ the result obtained is

$x^{2} -14x+49$

Hence, the correct option is (c)