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3 years ago

If x^2-13x+42=(x+A)(x+B), then find the value of 3A-B

Mathematics

1 answer:

tigry1 [53]3 years ago

5 0

Answer:

- 11 or - 15

Step-by-step explanation:

Factorise

x² - 13x + 42

Consider the factors of the constant term (+ 42) which sum to give the coefficient of the x- term (- 13)

The factors are - 6 and - 7, since

- 6 × - 7 = + 42 and - 6 - 7 = - 13, thus

x² - 13x + 42 = (x - 6)(x - 7)

compare to (x + A)(x + B)

A = - 6, B = - 7

thus 3A - B = 3(- 6) - (- 7) = - 18 + 7 = - 11

The factors may also be expressed as (x - 7)(x - 6)

with A = - 7 and B = - 6, then

3A - B = 3(- 7) - (- 6) = - 21 + 6 = - 15

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Answer:

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3 years ago

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marshall27 [118]

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larisa86 [58]

Answer:

<h2>Your Answer is C!!!!!!!!!</h2>

Steps:

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Katyanochek1 [597]

$\huge\text{Hey there!}$

$\large\text{Just do PEMDAS}$

$\large\text{Parentheses}$

$\large\text{Exponents}$

$\large\text{Multiplication}$

$\large\text{Division}$

$\large\text{Addition}$

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$\boxed{\boxed{\large\text{Answer: \bf \huge12 }}}\huge\checkmark$

$\text{Good luck on your assignment and enjoy your day! }$

~ $\frak{Amphitrite1040:)}$

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