Question

$Factorise:4y^2-12y+9$

• A. $(7y-5)(7y-5)$
• B. $(5y-3)(5y-3)$
• C. $(2y-3)(2y-3)$
• D. $(2y-5)(2y-5)$

Answer 1

The correct option is C

$(2y-3)(2y-3)$

The given expression can be rewritten as,
$(2y{)}^2-2(2y\left)\right(3)+3^2.$
Comparing with the identity
$(a-b{)}^2=a^2-2ab+b^2$
we get,
$(2y{)}^2-2(2y\left)\right(3)+3^2$
$=(2y-3{)}^2$
$=(2y-3)(2y-3)$