All categories

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

You might be interested in

What is the answer to - 1/3 (x+6)=0

Sauron [17]

$(-\frac{1}{3})(x+6)=0\\\\\frac{1}{3}(x+6)*3=0*3\\\\-1(x+6)=0\\\\-(x+6)*-1=0*-1\\\\x+6=0\\\\x=-6$

3 0

3 years ago

Read 2 more answers

A. In a complete sentence, describe the angle relationship in the diagram. B. Find the value of x

xxTIMURxx [149]

Answer:

x = 30

Step-by-step explanation:

a) The sum of the angles along the line is 180°. That means ...

2x° +90° +x° = 180°

b) Subtracting 90° and dividing by 3° gives ...

3x° = 90°

x = 30

8 0

2 years ago

- 7th Grade Work -<br><br> Am I doing this correctly?

katrin2010 [14]

Answer:

yes i think

Step-by-step explanation:

5 0

2 years ago

Read 2 more answers

I really need this answered fast.....The coordinates of the vertices of △JKL are J(−5, −1) , K(0, 1) , and L(2, −5) . Which stat

dimulka [17.4K]

<span>JKL is a right triangle because JK ¯ ¯ ¯ ¯ ¯ is perpendicular to KL</span>

5 0

2 years ago

Read 2 more answers

50 PTS ANSWER ALL <3333333

11Alexandr11 [23.1K]

QUESTION 33

The length of the legs of the right triangle are given as,

6 centimeters and 8 centimeters.

The length of the hypotenuse can be found using the Pythagoras Theorem.

${h}^{2} = {6}^{2} + {8}^{2}$

${h}^{2} = 36+ 64$

${h}^{2} = 100$

$h = \sqrt{100}$

$h = 10cm$

Answer: C

QUESTION 34

The triangle has a hypotenuse of length, 55 inches and a leg of 33 inches.

The length of the other leg can be found using the Pythagoras Theorem,

${l}^{2} + {33}^{2} = {55}^{2}$

${l}^{2} = {55}^{2} - {33}^{2}$

${l}^{2} = 1936$

$l = \sqrt{1936}$

$l = 44cm$

Answer:B

QUESTION 35.

We want to find the distance between,

(2,-1) and (-1,3).

Recall the distance formula,

$d=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}$

Substitute the values to get,

$d=\sqrt{( - 1-2)^2+(3- - 1)^2}$

$d=\sqrt{( - 3)^2+(4)^2}$

$d=\sqrt{9+16}$

$d=\sqrt{25}$

$d = 5$

Answer: 5 units.

QUESTION 36

We want to find the distance between,

(2,2) and (-3,-3).

We use the distance formula again,

$d=\sqrt{( - 3-2)^2+( - 3- 2)^2}$

$d=\sqrt{( - 5)^2+( - 5)^2}$

$d=\sqrt{25+25}$

$d=\sqrt{50}$

$d=5\sqrt{2}$

Answer: D

8 0

2 years ago

Read 2 more answers