Question

$(2y+5)(2y+5)$ =

• A. $4y^2+10y+25$
• B. $4y^2+20y+25$
• C. $4y^2+20y+15$
• D. $y^2+20y+25$

Answer 1

The correct option is B $4y^2+20y+25$

$(2y+5)(2y+5)=(2y+5{)}^2$
Using the identity,
$(a+b{)}^2=a^2+2ab+b^2$,

$(2y+5{)}^2=(2y{)}^2+2\left(2y\right)\left(5\right)+5^2=4y^2+20y+25$