Step-by-step explanation:
HERE,
a=[tex]\bold{\dfrac{1}{4} }[/tex]
b=6
so,
According to the question,
[tex]\bold{16a^2-4b }[/tex]
[tex]\bold{16\times(\dfrac{1}{4})^2-4\times 6 }[/tex]
[tex]\bold{ 16\times \dfrac{1}{16}-24 }[/tex]
[tex]\bold{\cancel{16}\times \dfrac{1}{\cancel{16}}-24 }[/tex]
[tex]\bold{1-24 }[/tex]
[tex]\bold{ -23 }[/tex]