Question

Question 1(ii)

Use a suitable identity to get each of the following products:
$(2y+5)(2y+5)$

Answer 1

$(2y+5)(2y+5)=(2y+5{)}^2$ $\left[Usingtheidentity\right(a+b{)}^2=a^2+2ab+b^2]$ $=(2y{)}^2+2\times 2y\times 5+(5{)}^2$
$=4y^2+20y+25$