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4 years ago

Write the given phrase as an algebraic expression. Use the variable x to represent the unknown number.

1 answer:

5 0

Hello! I would love to help!

Let's start with this part of the equation: "the sum of a number and seven"

Alright. We know that x represents an unknown number. Do you see a part of the equation that could translate to "an unknown number?"

I see "a number." So let's fill X in for "a number.

Alright. So now we have "the sum of x and 7."

Next, let's remember that sum means adding. So we just need to 7 to x

X+7

So, now instead of "the sum of a number and 7" we have x+7.

Alright. Now we just have to do the "twice." When it is asking for "twice", it is asking us to multiply our answer by two. But we need to multiply both x and 7. The best way to do that is to put our "x+7" in parenthesis and put a two outside.

2(x+7)

That's your answer! 2(x+7)

Hope this helped! Comment if you have any questions!

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T<29. graph your inequality for problem number 3

Pepsi [2]

I graphed it. First you choose a number that’s less than 29 and greater than 29 which I chose 0 and 100 but it didn’t let me show the whole picture

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3 years ago

HALLP QUICKKKK

Rina8888 [55]

To solve this we are going to use the formula for speed: $S= \frac{d}{t}$
where
$S$ is the speed
$d$ is the distance
$t$ is the time

Let $S_{l}$ be the speed of the boat in the lake, $S_{a}$ the speed of the boat in the river, $t_{l}$ the time of the boat in the lake, and $t_{a}$ the time of the boat in the river.

We know for our problem that the current of the river is 2 km/hour, so the speed of the boat in the river will be the speed of the boat in the lake minus 2km/hour:
 $S_{a}=S_{l}-2$
We also know that in the lake the boat sailed for 1 hour longer than it sailed in the river, so:
 $t_{l}=t_{a}+1$

Now, we can set up our equations.
Speed of the boat traveling in the river:
 $S_{a}= \frac{6}{t_{a} }$
But we know that $S_{a}=S_{l}-2$ , so:
$S_{l}-2= \frac{6}{t_{a} }$ equation (1)

Speed of the boat traveling in the lake:
$S_{l}= \frac{15}{t_{l} }$
But we know that $t_{l}=t_{a}+1$ , so:
$S_{l}= \frac{15}{t_{a}+1}$ equation (2)

Solving for $t_{a}$ in equation (1):
$S_{l}-2= \frac{6}{t_{a} }$
$t_{a}= \frac{6}{S_{l}-2}$ equation (3)

Solving for $t_{a}$ in equation (2):
$S_{l}= \frac{15}{t_{a}+1}$
$t_{a}+1= \frac{15}{S_{l}}$
$t_{a}=\frac{15}{S_{l}}-1$
$t_{a}= \frac{15-S_{l}}{S_{l}}$ equation (4)

Replacing equation (4) in equation (3):
$t_{a}= \frac{6}{S_{l}-2}$
$\frac{15-S_{l}}{S_{l}}=\frac{6}{S_{l}-2}$

Solving for $S_{l}$ :
$\frac{15-S_{l}}{S_{l}}=\frac{6}{S_{l}-2}$
$(15-S_{l})(S_{l}-2)=6S_{l}$
$15S_{l}-30-S_{l}^2+2S_{l}=6S_{l}$
$S_{l}^2-11S_{l}+30=0$
$(S_{l}-6)(S_{l}-5)=0$
$S_{l}=6$ or $S_{l}=5$

We can conclude that the speed of the boat traveling in the lake was either 6 km/hour or 5 km/hour.

3 0

4 years ago

Mel received notice that his monthly health care rate will increase 20% next year. If Mel currently pays $150 per month for heal

sveta [45]

It will increase by $30

We need to convert the percentage to a decimal by dividing by 100. Then we multiply by the $150.

150 x 0.20 = 30

7 0

3 years ago

Which of the following is a complex number?

Elena L [17]

Answer:

4+9i

Step-by-step explanation:

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3 years ago

John is at a local bait shop; he wants to buy bait for his fishing trip. At the store, they are selling live bait for $12 a poun

ladessa [460]

12x + 7y=60
12x3=36
60-36=24
7y=24
24/7=3.blah blah blah
y=3 pretty much
but you only needed that first part wow i did all that for nothin

5 0

3 years ago