How do you multiply # (7x+2) (7x+2) #?

2 Answers
Dec 19, 2017

#49x^2+28x+4#

Explanation:

#"each term in the second factor is multiplied by each term"#
#"in the first factor"#

#rArr(color(red)(7x+2))(7x+2)#

#=color(red)(7x)(7x+2)color(red)(+2)(7x+2)#

#=(color(red)(7x)xx7x)+(color(red)(7x)xx2)+(color(red)(2)xx7x)+(color(red)(2)xx2)#

#=49x^2+14x+14x+4#

#=49x^2+28x+4#

Dec 19, 2017

You know that: #cxxc=c^2#

So, #(7x+2)(7x+2)=(7x+2)^2#

You should know that: #(a+b)^2=a^2+2ab+b^2#

So, #(7x+2)^2=(7x)^2+2xx7xxx2+2^2#

Notice that there is a major difference in #7x^2" and " (7x)^2#

#49x^2+28x+4#