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help on this algebra equation?
“solve 2x = x^2 - 8 using the quadratic formula. show all work.”
6 Answers
- ComoLv 72 years ago
x² - 2x - 8 = 0
x = [- b ± √ (b² - 4ac) ] / 2a
x = [ 2 ± √ (4 + 32) ] / 2
x = [ 2 ± 6 ] / 2
x = 4 , - 2
- DWReadLv 72 years ago
2x = x² - 8
x² - 2x - 8 = 0
quadratic formula:
x = [-(-2) ± √((-2)² - 4(1)(-8))]/(2(1))
= [2 ± √36]/2
= [2 ± 6]/2
= 4, -2
- KrishnamurthyLv 72 years ago
2x = x^2 - 8
x^2 - 2x - 8 = 0
x
= [-b +/- (b^2 - 4ac)^(1/2)] / 2a
= [2 +/- (4 + 32)^(1/2)] / 2
= 1 +/- 3
= -2 or 4
- billrussell42Lv 72 years ago
x² – 2x – 8 = 0
quadratic equation:
to solve ax² + bx + c = 0
x = [–b ± √(b²–4ac)] / 2a
x = [2 ± √(4+32)] / 2
x = [2 ± √(36)] / 2
x = [2 ± 6)] / 2
x = 1 ± 3
x = 4, –2
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- az_lenderLv 72 years ago
0 = x^2 - 2x - 8.
The "a,b,c" of this quadratic are 1, -2, and -8.
Therefore
x = -b/2a +/- (1/2a)*sqrt(b^2 - 4ac)
= 1 +/- (1/2)*sqrt(4+32)
= 1 +/- 3;
the solutions are +4 and -2.
- llafferLv 72 years ago
To use quadratic equation, you need your equation in standard form:
0 = ax² + bx + c
So to do that, subtract 2x from both sides and put in proper order:
2x = x² - 8
0 = x² - 2x - 8
Now substitute the following values into the equation and simplify:
a = 1
b = -2
c = -8
x = [ -b ± √(b² - 4ac)] / (2a)
x = [ -(-2) ± √((-2)² - 4(1)(-8))] / (2 * 1)
x = [ 2 ± √(4 + 32)] / 2
x = [ 2 ± √(36)] / 2
x = (2 ± 6) / 2
x = -4/2 and 8/2
x = -2 and 4