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2 years ago

Can someone do it and explain please? I don’t get it

Mathematics

1 answer:

Katen [24]2 years ago

8 0

Is it 60 degrees or 70 degrees? because 100 + 120 = 220
360 - 220 = 140
One side looks larger than the other tho so I am not sure.

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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

Statistics

user100 [1]

Answer:

Step-by-step explanation:

The lower bound is 10.5 and the upper bound is 15.9

Hope it helps!

8 0

1 year ago

Suppose y varies directly with x and y = 72 when x = 6. What direct variation equation relates x and y? What is the value of y w

iogann1982 [59]

Y=12x
When x=10
y=120

x:3 5 7
y:6 10 14
y=2x

3 0

2 years ago

Someone please help I don’t understand sad face

Bess [88]

-1 cus its -1 becus u -1 so u get -1

6 0

2 years ago

Read 2 more answers

What is the value of c?

Korolek [52]

Answer:

c=9

Step-by-step explanation:

it’s because from the angles, you can see that this is an isosceles triangle, there the two sides have to be the same.

5 0

1 year ago