# If #sqrt(x-1)=2#, what is #(x - 1)^2# ?

##### 2 Answers

Apr 22, 2018

#### Explanation:

Square both sides:

This causes the radical to cancel out:

Square both sides, again:

Apr 22, 2018

#### Explanation:

#color(blue)"square both sides"#

#"note that "sqrtaxxsqrta=(sqrta)^2=a#

#rArr(sqrt(x-1))^2=2^2#

#rArrx-1=4#

#color(blue)"square both sides"#

#(x-1)^2=4^2#

#rArr(x-1)^2=16#