Answer:
16x² − 56x + 49
Step-by-step explanation:
The square of difference of two terms can be expressed as a perfect square trinomial in the following manner:
[tex](a-b)^{2}=a^{2}-2ab+b^{2}[/tex]
The symbol with square terms must be always positive. So this removes the first two options from the given choices. The correct option is either c or d.
Only the option d can be expressed as a perfect square as shown below:
[tex]16x^{2}-56x+49\\\\ = (4x)^{2}-2(4x)(7)+(7)^{2}\\\\ =(4x - 7)^{2}[/tex]
Option c would have been correct if it was -30b instead of -15b i.e. the middle term is twice the product of first and second term.
So, option D is correct
