Solve for "x"...
x^2 - 18x + 81 = 0
First: multiply the 1st & 3rd term to get 81. find two numbers that give you 81 when multiplied & -18 (2nd term) when added/subtracted. the numbers are (-9 & -9). rewrite the expression with the new middle terms.
x^2 - 9x - 9x + 81 = 0
Sec: group "like" terms; factor both sets of parenthesis.
(x^2 - 9x) - (9x + 81) = 0
x(x-9) - 9(x-1) = 0
(x-9)(x-9) = 0
(x-9)^2 = 0
Third: eliminate the exponent - find the square root of both sides.
V`(x-9)^2 = V`0
x - 9 = 0 (add 9 to both sides - when you move a term to the opposite side, always use the opposite sign).
x - 9+9 = 0+9
x = 9
2007-06-15 12:06:49
·
answer #1
·
answered by ♪♥Annie♥♪ 6
·
0⤊
0⤋
x^2 - 18x +81 = 0
(x-9)(x-9) = 0
Therefore, x = 9
2007-06-15 09:00:49
·
answer #2
·
answered by Werts 1
·
0⤊
0⤋
As written: x² = -80 one ?x² =?(-80 one) = ?80 one* ?(-a million) bear in mind ?(-a million) = i x= ±9i yet once you meant: x² + 18x = -80 one x² + 18x + 80 one =0 (x + 9)² = 0 x - 9 = 0 x = 9 it particularly is a double root(answer)
2016-11-24 22:22:44
·
answer #3
·
answered by thorpe 4
·
0⤊
0⤋
x² - 18x + 81 = 0
(x - 9).(x - 9) = 0
x = 9 (twice)
2007-06-16 03:45:27
·
answer #4
·
answered by Como 7
·
0⤊
0⤋
x^(2)-18x+81=0
(x-9) * (x-9) = 0
x = 9
2007-06-15 08:59:24
·
answer #5
·
answered by atheistforthebirthofjesus 6
·
0⤊
0⤋
x^(2) -18x+81=0
(x -9)*(x-9) = 0
x = 9 (double root)
2007-06-15 08:59:36
·
answer #6
·
answered by mark r 4
·
0⤊
0⤋
two numbers that multiply to 81 and add to -18
the two numbers are -9 and -9
(x - 9) (x - 9) = 0 or (x-9)^2 = 0
x = 9
2007-06-15 09:04:17
·
answer #7
·
answered by 7
·
0⤊
0⤋
x^2 - 18x + 81 = (x - 9)^2, so now it's boringly simple to find out the root..
Regards
Tonio
2007-06-15 08:59:16
·
answer #8
·
answered by Bertrando 4
·
0⤊
1⤋
factor into (x-9)(x-9)=0, a number times 0 equals 0 so you know that x-9=0, and x equals 9.
2007-06-15 09:00:59
·
answer #9
·
answered by Joe 2
·
0⤊
1⤋
its a quadratic equation so use the quatratic equation, u should of learn or easily find on line
2007-06-15 08:59:34
·
answer #10
·
answered by Anonymous
·
0⤊
1⤋