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3 years ago

Janelle expanded the expression as shown below. -4(-3x + 2/7) = -12x - 3 5/7 What errors did she make? Select three options

Mathematics

1 answer:

scZoUnD [109]3 years ago

8 0

Answer:

Step-by-step explanation:

Janelle expanded the expression as shown below. -4(-3x + 2/7) = -12x - 3 5/7 What errors did she make?

We are given the expression:

-4(-3x + 2/7)

Solving this expression:

Expanding the brackets

-4 × -3x + -4 × 2/7

12x - 8/7

12x - 1 1/7

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Write the following integers in a decreasing order. 1. 0,7,-3,9,-132,36

Elan Coil [88]

ANSWER:
36 > 9 > 7 > 0 > -3 > -132

Hope it helps u!

6 0

2 years ago

Read 2 more answers

The difference of six times a number and 7 is -49

gtnhenbr [62]

Greetings!

"The difference of six times a number and 7 is -49"...

In number and variables, this would be:
 $6x-7=-49
$

Add 7 to both sides.
 $(6x-7)+7=(-49)+7$
Simplify.
 $6x=-42$
Divide both sides by 6.
$(6x)/6=(-42)/6$
Simplify.
$x=-7$

Hope this helps.
-Benjamin

5 0

3 years ago

What expression can be used to add 7/10 + 13/20

lora16 [44]

0.7+0.65 I’m not sure this is what u were looking for but I hope it helps have a good one

4 0

2 years ago

NASA launches a rocket at t = 0 seconds. Its height, in meters above sea-level, as a function of time is given by h ( t ) = − 4.

Oliga [24]

Answer:

$\displaystyle 1)48.2 \: \: \text{sec}$

$\rm \displaystyle 2)3021.6 \: m$

Step-by-step explanation:

<h3>Question-1:</h3>

so when flash down occurs the rocket will be in the ground in other words the elevation(height) from ground level will be 0 therefore,

to figure out the time of flash down we can set h(t) to 0 by doing so we obtain:

$\displaystyle - 4.9 {t}^{2} + 229t + 346 = 0$

to solve the equation can consider the quadratic formula given by

$\displaystyle x = \frac{ - b \pm \sqrt{ {b}^{2} - 4 ac} }{2a}$

so let our a,b and c be -4.9,229 and 346 Thus substitute:

$\rm\displaystyle t = \frac{ - (229) \pm \sqrt{ {229}^{2} - 4.( - 4.9)(346)} }{2.( - 4.9)}$

remove parentheses:

$\rm\displaystyle t = \frac{ - 229 \pm \sqrt{ {229}^{2} - 4.( - 4.9)(346)} }{2.( - 4.9)}$

simplify square:

$\rm\displaystyle t = \frac{ - 229 \pm \sqrt{ 52441- 4( - 4.9)(346)} }{2.( - 4.9)}$

simplify multiplication:

$\rm\displaystyle t = \frac{ - 229 \pm \sqrt{ 52441- 6781.6} }{ - 9.8}$

simplify Substraction:

$\rm\displaystyle t = \frac{ - 229 \pm \sqrt{ 45659.4} }{ - 9.8}$

by simplifying we acquire:

$\displaystyle t = 48.2 \: \: \: \text{and} \quad - 1.5$

since time can't be negative

$\displaystyle t = 48.2$

hence,

at 48.2 seconds splashdown occurs

<h3>Question-2:</h3>

to figure out the maximum height we have to figure out the maximum Time first in that case the following formula can be considered

$\displaystyle x _{ \text{max}} = \frac{ - b}{2a}$

let a and b be -4.9 and 229 respectively thus substitute:

$\displaystyle t _{ \text{max}} = \frac{ - 229}{2( - 4.9)}$

simplify which yields:

$\displaystyle t _{ \text{max}} = 23.4$

now plug in the maximum t to the function:

$\rm \displaystyle h(23.4)- 4.9 {(23.4)}^{2} + 229(23.4)+ 346$

simplify:

$\rm \displaystyle h(23.4) = 3021.6$

hence,

about 3021.6 meters high above sea-level the rocket gets at its peak?

5 0

2 years ago

What happens to the energy not output by a machine

Sveta_85 [38]

Answer:

By using the energy conservation law, the input energy must be equivalent to the output energy. If you measured output energy is lower than your input energy, you have lost that difference of energy either in mechanical inefficiency (friction, heat, etc.) or an energy sink.

Thus, the energy not output by the machine is lost in the process within the machine.

Cheers.

5 0

3 years ago