How do you solve #sqrt(x-1)=-3#?

2 Answers
May 14, 2016

Answer:

#x=4#

Explanation:

Square both sides

#x-1=3#

#color(blue)("Shortcut method")#

Move the -1 to the other side of the equals
#x=3+1#

#x=4#

'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#color(blue)("First principle method")#

Add 1 to both sides

#x-1+1=3+1#

#x+0=4#

#x=4#

May 14, 2016

Answer:

10

Explanation:

#sqrt(x-1)=-3#
squaring both sides
#x-1=9#
#x=1+9#
#x=10#
valid for negative #sqrt(x-1)#