Factoring x2+8x15=0?
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Factor please! X=? and other X=
Update : its X(squared)
X^2+8x15=0
X^2+8x15=0
Update 2: NEGITIVE X SQUARED. PLUS EIGHT X. MINUS FIFTEEN. EQUALS ZERO
Best Answer
since multiplication is commutative x2 is the same as 2x
2x + 8x  15 = 0
10x  15 = 0
10x = 15
x = 15/10 = 3/2. <==== Solution
EDIT: 2300 hours. Thursday, Oct. 20, 2011
Given: x² + 8x  15 = 0
Not factorable, so use completing the square to solve.
x² + 8x + ☺ = ☺ + 15
☺ = (8/2)² = 16
x² + 8x + 16 = 16 + 15
(x + 4)² = 31
Take ±√ of both sides
x + 4 = ±√31
x = ±√31  4 <==== Solution
Reference: http://www.wolframalpha.com/input/?i=x%C...
EDIT: I just noticed you had x² + 8x  15 = 0
divide or multiply through by a 1.
x²  8x + 15 = 0
Find two factors of 15 that sum to 8.
Those factors are 3 and 5.
(x  3)(x  5) = 0
x  3 = 0 or x  5 = 0
x = 3 or x = 5. <==== Solution
2x + 8x  15 = 0
10x  15 = 0
10x = 15
x = 15/10 = 3/2. <==== Solution
EDIT: 2300 hours. Thursday, Oct. 20, 2011
Given: x² + 8x  15 = 0
Not factorable, so use completing the square to solve.
x² + 8x + ☺ = ☺ + 15
☺ = (8/2)² = 16
x² + 8x + 16 = 16 + 15
(x + 4)² = 31
Take ±√ of both sides
x + 4 = ±√31
x = ±√31  4 <==== Solution
Reference: http://www.wolframalpha.com/input/?i=x%C...
EDIT: I just noticed you had x² + 8x  15 = 0
divide or multiply through by a 1.
x²  8x + 15 = 0
Find two factors of 15 that sum to 8.
Those factors are 3 and 5.
(x  3)(x  5) = 0
x  3 = 0 or x  5 = 0
x = 3 or x = 5. <==== Solution
Source:
Math Professor ☺
Other Answers (2)
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I do not think that this equation is factor able. I might be wrong but i think that there are no real solutions.

first learn to write the equation properly!
its 2x + 8x  15 = 0Source(s):
where probably doing your homework for you so why not atleast ask it correctly?
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