How do you factor completely #a^2 - 121b^2#?

2 Answers
Jun 13, 2018

Answer:

#a^2-121b^2 = (a-11b)(a+11b)#

Explanation:

The difference of sqares identity can be written:

#A^2-B^2 = (A-B)(A+B)#

Given:

#a^2-121b^2#

Note that both #a^2# and #121b^2 = (11b)^2# are perfect sqares.

So we can use the difference of squares identity with #A=a# and #B=11b# to find:

#a^2-121b^2 = a^2-(11b)^2 = (a-11b)(a+11b)#

Jun 13, 2018

Answer:

Shown below...

Explanation:

Use difference of two squares:

#(A^2-B^2) = (A+B)(A-B) #

#=> ( (a)^2 - (11b)^2 ) #

#=> (a+11b)(a-11b) #