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2 years ago

Question 9 of 10

Mathematics

1 answer:

Liula [17]2 years ago

7 0

Answer:

Step-by-step explanation:

20x + 12 x =14x +30

20x - 14x = 30-12

6x= 18

6x/6 = 18/6

x = 3

so xs =3

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3 years ago

Sean tossed a coin off a bridge into the stream below. The path of the coin can be represented by the equation 2 h tt = − 16t^2+

tekilochka [14]

Answer:

It will take 5.61 seconds for the coin to reach the stream.

Step-by-step explanation:

The height of the coin, after t seconds, is given by the following equation:

$h(t) = -16t^{2} + 72t + 100$

How long will it take the coin to reach the stream?

The stream is the ground level.

So the coin reaches the stream when h(t) = 0.

$h(t) = -16t^{2} + 72t + 100$

$-16t^{2} + 72t + 100 = 0$

Multiplying by (-1)

$16t^{2} - 72t - 100 = 0$

Solving a quadratic equation:

Given a second order polynomial expressed by the following equation:

$ax^{2} + bx + c, a\neq0$ .

This polynomial has roots $x_{1}, x_{2}$ such that $ax^{2} + bx + c = a(x - x_{1})*(x - x_{2})$ , given by the following formulas:

$x_{1} = \frac{-b + \sqrt{\bigtriangleup}}{2*a}$

$x_{2} = \frac{-b - \sqrt{\bigtriangleup}}{2*a}$

$\bigtriangleup = b^{2} - 4ac$

In this question:

$16t^{2} - 72t - 100 = 0$

$a = 16, b = -72, c = -100$

$\bigtriangleup = (-72)^{2} - 4*16*(-100) = 11584$

$t_{1} = \frac{-(-72) + \sqrt{11584}}{2*16} = 5.61$

$t_{2} = \frac{-(-72) - \sqrt{11584}}{2*16} = -1.11$

Time is a positive measure, so we take the positive value.

It will take 5.61 seconds for the coin to reach the stream.

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Answer:

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Step-by-step explanation:

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3 years ago

9 + 5 = x - 11<br>how to find the x number

astra-53 [7]

9 + 5 = x - 11

combine like terms

14 = x - 11

add 11 to both sides

25 = x

x = 25

answer

x = 25

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3 years ago

Read 2 more answers