2007-10-20 13:32:50 · 9 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
[05]
x^2-1=80
x^2=80+1=81
x=+-9 [square-rooting both sides]
2007-10-20 13:38:07 · answer #1 · answered by alpha 7 · 0⤊ 2⤋
Step1: Write out the original equation
x^2-1=80
Step 2: Get the variable by itself (by adding one in this case)
x^2=81
Step 3: Take the square root of both sides
X^2=9 or -9
***REMEMBER... when square rooting both sides, it is ALWAYS positive OR negative***
Hope this helps!
2007-10-20 20:53:21 · answer #2 · answered by Brie 2 · 0⤊ 1⤋
Move -1 to the other side becomes x^2=80+1
remember as soon as you move something across the = change the sign
80+1 = 81
next take the square root of both sides sqrt(x^2) = x
sqrt of 81 =9
x=+-9
2007-10-20 20:36:48 · answer #3 · answered by Smokey. 6 · 0⤊ 4⤋
x^2-1=80
Add 1 to each side
x^2=81
We will now take the square root of each side
x=+-9
We get +-9 becuase (-9)^2 and 9^2 gives us the exact same answer.
2007-10-20 20:40:18 · answer #4 · answered by aba 2 · 0⤊ 0⤋
Move the add 1 to both sides. X^2=81. Take square root of both sides. x=9 and -9.
2007-10-20 20:36:50 · answer #5 · answered by Mal 5 · 0⤊ 4⤋
x^2 - 1 - 80 = 0
x^2 - 81 = o
(x-9) (x+9) = 0
so x1= 9 ; x2 = -9
2007-10-20 20:37:24 · answer #6 · answered by UJ 3 · 1⤊ 1⤋
x^2 = 81
x = +9 and x = -9
2007-10-20 20:36:59 · answer #7 · answered by fcas80 7 · 1⤊ 2⤋
x² = 81
x = ± 9
2007-10-21 08:35:19 · answer #8 · answered by Como 7 · 1⤊ 1⤋
9,-9
2007-10-20 20:39:06 · answer #9 · answered by UNIQUE 3 · 0⤊ 0⤋