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

2 Answers
VNVDVI
Apr 22, 2018

#(x-1)^2=16#

Explanation:

Square both sides:

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

This causes the radical to cancel out:

#(x-1)=4#

Square both sides, again:

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

#(x-1)^2=16#

Jim G.
Apr 22, 2018

#(x-1)^2=16#

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#

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