Question

Multiply : $(3a-\frac{1}{2})(3a-\frac{1}{2})$

• A. $9a^2-3a+\frac{1}{4}$
• B. $3a^2-3a+\frac{1}{4}$
• C. $3a^2-a+\frac{1}{4}$
• D. $9a^2-3a+\frac{1}{2}$

Answer 1

Answer: (A)

$9a^2-3a+\frac{1}{4}$

$(3a-\frac{1}{2})(3a-\frac{1}{2})$
Using ,
$(ab{)}^2=a^2+2ab+b^2$, we get the above equation.
$=(3a{)}^2-2\times 3a\times \frac{1}{2}+(\frac{1}{2}{)}^2$
$=9a^2-3a+\frac{1}{4}$