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3 years ago

Jason's mom drove at 100km/hr for a 160km trip.how much longer would the trip have taken if she had driven at 90km/hr

1 answer:

kondor19780726 [428]3 years ago

3 0

We use the formule: t=S/v. So:
+ t1= 160/100 = 8/5 hrs = 5760''
+ t2= 160/90 = 16/9 hrs = 6400''

=> t2-t1= 6400 - 5760 = 640'' = 10'40''

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Which of the following is the complete list of roots for the polynomial function f (x) = (x2 + 6x + 8) (x2 + 6x + 13)?

Natali5045456 [20]

Answer:

-2, -4, -3 + 2i, -3-2i

Step-by-step explanation:

Equaling the function to zero we have:

(x ^ 2 + 6x + 8) (x ^ 2 + 6x + 13) = 0

For the first parenthesis we have:

(x ^ 2 + 6x + 8) = 0\\(x + 4) (x + 2) = 0

Therefore the roots are:

x = - 4\\x = - 2

For the second parenthesis we have:

(x ^ 2 + 6x + 13) = 0

By completing squares we have:

x ^ 2 + 6x = -13

x ^ 2 + 6x + (\frac{6}{2}) ^ 2 = -13 + (\frac{6}{2}) ^ 2\\x ^ 2 + 6x + 9 = -13 + 9\\(x + 3) ^ 2 = - 4\\x + 3 = +/- \sqrt{-4}

Therefore the roots are:

x = -3 + 2i\\x = -3 - 2i

Hope this was helpful

6 0

3 years ago

A number added to itself twelve times is five more than twice the number. What is the number?

zaharov [31]

$x- \ searching\ number\\\\
x+12x=2x+5\\
13x-2x=5\\
11x=5\ |:11\\
x=\frac{5}{11}\\\\
The\ number\ is\ \frac{5}{11},
$

8 0

3 years ago

Urgent, It is a Calculus question and I’ll appreciate your help. Thanks

BaLLatris [955]

Answer:

4733

Step-by-step explanation:

Please refer to the attached diagram.

Point A can be assigned x-coordinate "p". Then its y-coordinate is 6p^2. The slope at that point is y'(p) = 12p.

Point B can be assigned x-coordinate "r". Then its y-coordinate is 6r^2. The slope at that point is y'(r) = 12r.

We want the slopes at those points to have a product of -1 (so the tangents are perpendicular). This means ...

(12p)(12r) = -1

r = -1/(144p)

The slope of line AB in the diagram is the ratio of the differences of y- and x-coordinates:

slope AB = (ry -py)/(rx -px) = (6r^2 -6p^2)/(r -p) = 6(r+p) . . . . simplified

The slope of AB is also the tangent of the sum of these angles: the angle AC makes with the x-axis and angle CAB. The tangent of a sum of angles is given by ...

tan(α+β) = (tan(α) +tan(β))/1 -tan(α)·tan(β))

Of course the slope of a line is equal to the tangent of the angle it makes with the x-axis. The tangent of angle CAB is 2 (because the aspect ratio of the rectangle is 2). This means we can write ...

slope AB = ((slope AC) +2)/(1 -(slope AC)(2))

$6(p+r)=\dfrac{12p+2}{1-(12p)(2)}\\\\3(p+r)(1-24p)=6p+1\qquad\text{multiply by $1-24p$}\\\\3\left(p-\dfrac{1}{144p}\right)(1-24p)=6p+1\qquad\text{use the value for r}\\\\3(144p^2-1)(1-24p)=144p(6p+1)\qquad\text{multiply by 144p}\\\\ 3456 p^3+ 144 p^2+ 24 p+1 =0\qquad\text{put in standard form}\\\\144p^2(24p+1)+(24p+1)=0\qquad\text{factor by pairs}\\\\(144p^2+1)(24p+1)=0\qquad\text{finish factoring}\\\\p=-\dfrac{1}{24}\qquad\text{only real solution}\\\\r=\dfrac{-1}{144p}=\dfrac{1}{6}$

So, now we can figure the coordinates of points A and B, and the distance between them. That distance is given by the Pythagorean theorem as ...

d^2 = (6r^2 -6p^2)^2 +(r -p)^2

d^2 = (6(1/6)^2 -6(-1/24)^2)^2 +(1/6 +1/24)^2 = 25/1024 +25/576 = 625/9216

Because of the aspect ratio of the rectangle, the area is 2/5 of this value, so we have ...

Rectangle Area = (2/5)(625/9216) = 125/4608 = a/b

Then a+b = 125 +4608 = 4733.

_____

<em>Comment on the solution</em>

The point of intersection of the tangent lines is a fairly messy expression, and that propagates through any distance formulas used to find rectangle side lengths. This seemed much cleaner, though maybe not so obvious at first.

6 0

3 years ago

Combining like terms with rational coefficients <br> 7/8m+9/10-2m-3/5

nikklg [1K]

Answer:

Ah yes, one of my favorite topics.

Step 1: Which ever fraction comes first, you will solve it first. For this question, focus on doing $\frac{7}{8}m-2m$ first. Afterwards, do $\frac{9}{10}-\frac{3}{5}$