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3 years ago

12

Find the value of y if x equals 20? -2x+4y=-4

2 answers:

sammy [17]3 years ago

4 0

x=20

-2(20) + 4(y) =-4

-40+4y=-4

-4y=-36

y=9

Digiron [165]3 years ago

3 0

Y= 9

-2(20)+4y=-4
-40+4y=-4
-36=-4y
9=y

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HELP ME !!! PLEASE and thank you

PIT_PIT [208]

$\dfrac{MN}{ML}=\dfrac{HG}{HI}\\
\dfrac{MN}{18}=\dfrac{12}{27}\\
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6 0

3 years ago

pls solve quickly!: It took a boat 2 hours to reach town A going upstream. The way back was 1h20 min. What is the speed of the b

goldenfox [79]

Answer:

15 mph

Step-by-step explanation:

Given: Boat took 2 hours to reach Town A going upstream.

Speed of stream= 3 mph

Time taken to reach back home= 1 hours 20 minutes

Lets assume distance covered one side be "d" and speed of boat in still water be "s".

∴ Speed of boat in upstream= $(s-3) \ mph$

Speed of boat in downstream= $(s+3)\ mph$

Also converting into fraction of time taken to reach back home.

Remember; 1 hour= 60 minutes

∴ Time taken to reach back home= $60+20= 80\ minutes$

Converting time given into fraction= $\frac{80\ minutes}{60\ minutes} = \frac{4}{3} \ hours$

hence, Time taken to reach back home is $\frac{4}{3} \ hours$

Now forming equation of boat travelling upstream and downstream, considering distance remain constant.

We know, $Distance= speed \times time$

⇒ $(s-3)\times 2= (s+3)\times \frac{4}{3}$

Using distributive property of multiplication

⇒ $2s-6= \frac{4}{3}s +4$

subtracting both side by $\frac{4}{3} s$

⇒ $2s-\frac{4}{3} s-6= 4$

Adding both side by 6

⇒ $2s-\frac{4}{3} s= 10$

taking LCD as 3

⇒ $\frac{2}{3} s= 10$

Multiplying both side by $\frac{3}{2}$

⇒ $s= \frac{3}{2} \times 10$

∴s= 15 mph

Hence, 15 mph is the speed of the boat in still water.

8 0

3 years ago

Add or subtract them in simplest form please help me as fast as possible

NARA [144]

Answer:

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Step-by-step explanation:

Look for a commen donominater of the 3/8 and 1/3 the denominater would be 24 so 8 times 3 and 3 times 3 so those would be 9/24 and 3/24 , do the 8 plus the ten and you get 18 so 18+ 9/24+3/24= 18 12/24, or 18 1/2

8 0

3 years ago

Select from the drop-down menus to correctly complete the statements about the expression 5k+m3 .

Setler [38]

Answer:

sum

Step-by-step explanation:

4 0

2 years ago

Complete the work to find the dimensions of the rectangle. x(x – 3) = 10 x2 – 3x = 10 x2 – 3x – 10 = 10 – 10 (x + 2)(x – 5) = 0

Norma-Jean [14]

Answer:

$Length =5$

$Width = 2$

Step-by-step explanation:

Given

$Length =x$

$Width = x -3$

$Area = 10$

$x(x-3) =10$

See comment for missing part of the question

Required

Complete the expression to determine the dimension of a rectangle

We have:

$x(x-3) =10$

Open bracket

$x^2 -3x = 10$

Equate to 0

$x^2 -3x - 10 =0$

Expand

$x^2 + 2x - 5x - 10 = 0$

Factorize

$x(x + 2) - 5(x + 2) = 0$

Factor out x + 2

$(x - 5)(x + 2) = 0$

Solve for x

$x - 5 = 0$ or $x + 2 = 0$

$x = 5$ or $x = -2$

The value of x cannot be negative

So:

$x = 5$

Recall that:

$Length = x$

$Width = x - 3$

So:

$Length =5$

$Width = 2$ ---- i.e. 5 - 3

6 0

3 years ago