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Solve the quadratics attached using at least two different methods (factoring, completing the square or the quadratic formula)


m^2+7m+10\\\\n^2\:+9n+18\\\\\\p^2-6p+8

1 Answer

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Method 1: Factoring

m^2 + 7m + 10

We need to find two numbers that multiply to 10 and add up to 7. These numbers are 2 and 5.

m^2 + 2m + 5m + 10

(m + 2)(m + 5)

n^2 + 9n + 18

We need to find two numbers that multiply to 18 and add up to 9. These numbers are 3 and 6.

n^2 + 3n + 6n + 18

(n + 3)(n + 6)

p^2 - 6p + 8

We need to find two numbers that multiply to 8 and add up to -6. There are no such numbers, so we cannot factor this quadratic.

Method 2: Quadratic Formula

m^2 + 7m + 10

a = 1, b = 7, c = 10

m = (-b ± sqrt(b^2 - 4ac)) / 2a

m = (-7 ± sqrt(7^2 - 4(1)(10))) / 2(1)

m = (-7 ± sqrt(9)) / 2

m = -5 or -2

n^2 + 9n + 18

a = 1, b = 9, c = 18

n = (-b ± sqrt(b^2 - 4ac)) / 2a

n = (-9 ± sqrt(9^2 - 4(1)(18))) / 2(1)

n = (-9 ± sqrt(9)) / 2

n = -3 or -6

p^2 - 6p + 8

a = 1, b = -6, c = 8

p = (-b ± sqrt(b^2 - 4ac)) / 2a

p = (6 ± sqrt(6^2 - 4(1)(8))) / 2(1)

p = (6 ± sqrt(16)) / 2

p = 2 or 4

Therefore, the solutions to the quadratics are:

m^2 + 7m + 10 = (m + 2)(m + 5) or m = -5 or -2

n^2 + 9n + 18 = (n + 3)(n + 6) or n = -3 or -6

p^2 - 6p + 8 = (p - 2)(p - 4) or p = 2 or 4

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