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3 years ago

Fifteen less than a number

Mathematics

1 answer:

skelet666 [1.2K]3 years ago

5 0

Answer:

A number -15

x-15

x= that number

Step-by-step explanation:

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1.) Use the quadratic formula to solve the equation. If necessary, round to the nearest hundredth .x squared minus 21 x equals n

Andrew [12]

Part 1
We are given $x^2-21x=-4x$ . This can be rewritten as $x^2-18x=0$ .
Therefore, a=1, b=-18, c=0.
Using the quadratic formula
$x=\frac{-b\pm \sqrt{b^2-4ac}}{2a}=\frac{-\left(-18\right)\pm \sqrt{\left(-18\right)^2-4\left(1\right)\left(0\right)}}{2\left(1\right)}$
$x=\frac{18\pm 18}{2}$

The values of x are
$x_1=\frac{18-18}{2}=0$
$x_2=\frac{18+18}{2}=18$

Part 2
Since the values of y change drastically for every equal interval of x, the function cannot be linear. Therefore, the kind of function that best suits the given pairs is a quadratic function.

Part 3.
The first equation is $y=x^2+2$ .
The second equation is $y=3x+20$ .

We have
$x^2+2=3x+20$
$x^2-3x-18=0$
Factoring, we have
$\left(x-6\right)\left(x+3\right)=0$
Equating both factors to zero.
$x_1-6=0\rightarrow x_1=6$
$x_2+3=0\rightarrow x_2=-3$

When the value of x is 6, the value of y is
$y=3\left(6\right)+20=38$

When the value of x is -3, the value of y is
$y=3\left(-3\right)+20=11$

Therefore, the solutions are (6,38) or (-3,11)

7 0

3 years ago

Slope for (6,5) (14, -3)

otez555 [7]

Answer:

m= -1

I hope this helped, have a great day!! <3

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3 years ago

Write an expression to represent the perimeter of:

kotykmax [81]

"Perimeter" is the distance all the way around the drawing. If the drawing has sides, then the perimeter is the SUM of the lengths of all the sides. It's exactly the distance an ant would have to walk along the line, to get all the way around to where he started from.

To get the perimeter of the triangle, you have to add up the lengths of the three sides.

(2a - 3) + (2a) + (3a + 1) =

2a - 3 + 2a + 3a + 1 .

Add up all the 'a's: 2a + 2a + 3a = 7a

Add up all the just plain numbers: -3 + 1 = -2

Write them together, as a binomial: 7a - 2

THAT's your expression for the perimeter.

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3 years ago

Find the zeros of the function by factoring 3x^2+ 10x=8

Wittaler [7]

Answer:

$x=\frac{2}{3}, -4$

Step-by-step explanation:

hope this helps!

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3 years ago

What type of function is represented in the table of values shown below ?

Murljashka [212]

I’m going to go with Exponential

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3 years ago