Answer:
b.[tex](2k+5r)(2k-5r)[/tex]
Step-by-step explanation:
We have to find the equation which are true identity.
a.[tex](3-2y)(2y-3x)[/tex]
[tex](3x-2y)(2y-3x)=3x(2y-3x)-2y(2y-3x)[/tex]
[tex]=6xy-9x^2-4y^2+6xy[/tex]
[tex](3-2y)(2y-3x)\neq 9x^2-4y^2[/tex]
b.[tex](2k+5r)(2k-5r)[/tex]
[tex](2k)^2-(5r)^2[/tex]
Using identity
[tex](a+b)(a-b)=a^2-b^2[/tex]
[tex]4k^2-25r^2[/tex]
It is true.
Hence, option b is true.
