What numbers multiply to 6 and add up to 9

1 answer:

Nookie1986 [14]3 years ago

6 0

Xy = 6
x + y = 9

x + y = 9
x - x + y = -x + 9
y = -x + 9

  xy = 6
  x(-x + 9) = 6
  x(-x) + x(9) = 6
-x² + 9x = 6
  -x² + 9x - 6 = 0
-1(x²) - 1(-9x) - 1(6) = 0
-1(x² - 9x + 6) = 0
-1 -1
x² - 9x + 6 = 0
x = -(-9) ± √((-9)² - 4(1)(6))
2(1)
x = 9 ± √(81 - 24)
2
x = 9 ± √(57)
2
x = 4.5 ± 0.5√(57)

x + y = 9
4.5 ± 0.5√(57) + y = 9
- (4.5 ± 0.5√(57)) - (4.5 ± 0.5√(57))
y = 4.5 ± 0.5√(57)
(x, y) = (4.5 ± 0.5√(57), 4.5 ± 0.5√(57))

The two numbers that multiply to 6 and add up to 9 are 4.5 ± 0.5√(57).

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Can somebody help me make sure this is correct

My name is Ann [436]

$x\in\{-3;-2.2;-2;0;1.5;3;4\}\\\\-3\leq x\leq4$

x = -3 → -3 = -3 and -3 < 4 therefore -3 ≤ -3 ≤ 4
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Step-by-step explanation: