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3 years ago

14

PLS!!! HELP ME!!!! I WILL MARK U!!

1 answer:

SOVA2 [1]3 years ago

7 0

Answer:

-47.4

Step-by-step explanation:

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A bridge in the shape of an arch connects two cities separated by a river. The two ends of the bridge are located at (–7, –13) a

sdas [7]

Answer:

$y=-\dfrac{13}{49}x^2$

Step-by-step explanation:

The shape of an arch corresponds to a parabola.

the general equation for a parabola is:

$y=ax^2+bx+c$

we're given three coordinates: (-7,-13),(7,-13) and (0,0)

so we can plug these values in the general equation to make 3 separate equations:

(x,y) = (-7,-13)

$-13=a(-7)^2+b(-7)+c$

$49a-7b+c=-13$

(x,y) = (7,-13)

$-13=a(7)^2+b(7)+c$

$49a+7b+c=-13$

(x,y) = (0,0)

$0=a(0)^2+b(7)+c$

$c=0$

so we have three equations. and we can solve them simultaneously to find the values of a,b, and c.

we've already found c = 0, let's use substitute it to other equations.

$49a-7b+c=-13\quad\Rightarrow\quad49a-7b=-13$

$49a+7b+c=-13\quad\Rightarrow\quad49a+7b=-13$

we can solve these two equation using the elimination method, by simply adding the two equations

$\quad\quad49a-7b=-13\\+\quad49a+7b=-13$

------------------------------

$\quad\quad 98a=-26$

$\quad\quad a=-\dfrac{13}{49}$

Now we can plug this value of a in any of the two equations.

$49a-7b=-13$

$49\left(-\dfrac{13}{49}\right)-7b=-13$

$-13-7b=-13$

$-7b=0$

$b=0$

We have the values of a,b, and c. We can plug them in the general equation to find the equation of the arch.

$y=\left(-\dfrac{13}{49}\right)x^2+0x+0$

$y=-\dfrac{13}{49}x^2$

$49y=-13x^2$

This our equation of the arch!

5 0

2 years ago

Will give Brainliest and Five Stars to the correct answer

nadezda [96]

The correct answer is y = 1/8x^2

5 0

2 years ago

Sarah completes 1/6 of a project in 1/4 of an hour at this rate how much of the project does Sarah complete per hour? Sarah comp

PtichkaEL [24]

Answer:

2/3

Step-by-step explanation:

Time it would take Sarah to complete the work in one hour = work completed in 1/4 hours x 4

We are multiplying by 4 because there are 4, 1/4 in an hour

1/4 + 1/4 + 1/4 + 1/4 = 1 hour

$\frac{1}{6}$ × 4 = $\frac{4}{6}$

To transform to the simplest form. divide both the numerator and the denominator by 2

= $\frac{2}{3}$

8 0

2 years ago

Look at the orange points on the graph. If the x-values a and c are 1 unit apart, how are the y-values b and d related?

ankoles [38]

Answer:

multiply 2 by b to get d

Step-by-step explanation:

4 0

2 years ago

Find the first term and the explicit formula a12=1/32 and r=1/2

Alexxx [7]

Answer:

see explanation

Step-by-step explanation:

The n th term of a geometric sequence is

$a_{n}$ = a $(r)^{n-1}$

where a is the first term and r the common ratio

Given $a_{12}$ = $\frac{1}{32}$ and r = $\frac{1}{2}$ , then

a $(\frac{1}{2}) ^{11}$ = $\frac{1}{32}$ , that is

$\frac{a}{2^{11} }$ = $\frac{1}{32}$

$\frac{a}{2048}$ = $\frac{1}{32}$ ( cross- multiply )

32a = 2048 ( divide both sides by 32 )

a = 64 ← first term

Thus the explicit formula is

$a_{n}$ = 64 $(\frac{1}{2}) ^{n-1}$

5 0

2 years ago