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2 years ago

Find the value of x for 3x + 4 = 25

Mathematics

2 answers:

Mila [183]2 years ago

7 0

Answer:

Step-by-step explanation:

If 3x + 4 = 25, the first step for solving for x will be to subtract 4 from both sides of the equation. This gives us 3x + 4 - 4 = 25 - 4, or 3x + 0 = 21, or 3x = 21. Now take 21 (from the right side of the equation) and divide by 3 (from the left side of the equation) to come up with x = 7.

Ugo [173]2 years ago

6 0

Answer:

Step-by-step explanation:

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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

Conjecture of the sum of the first 6 positive even numbers

ivann1987 [24]

Your answer would be 42

5 0

4 years ago

Tim's house has a taxable value of $ 149 , 000 . Tim's property tax rate is 0.28 % . How much will Tim have to pay in property t

AnnyKZ [126]

Answer:

$41,720

Step-by-step explanation:

4 0

3 years ago

Need help asap, please someone will help me understand this better

s2008m [1.1K]

Answer:

B.) $695.00

Step-by-step explanation:

To find interest on the money put into a savings account, you can use the equation I = Prt. I stands for interest. P stands for the principal (the money you put in). R stands for rate (3.5% annual simple interest). T stands for time. Now that you know what the formula means you can plug in your variables to find interest. I=400*3.5%*2 makes an interest of $28 which you can add to $400 to find $428 in your first account. In the second account I=250*3.25%*2 makes an interest of $16.25 which you can add to 250 to get $267.81. $267.81+$428=about$695.00

3 0

3 years ago

Two angles are called when their measures add to 180 degrees.

kirill115 [55]

Answer:

Two angles are called supplementary when their measures add up to 180 degrees.

Step-by-step explanation:

8 0

3 years ago

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