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3 years ago

Can someone please help me I really need help please help me

Mathematics

1 answer:

just olya [345]3 years ago

7 0

Oh okay. I think that what this is asking, is that they just want you to find the slopes.

So first you have to put both equations into y=mx+b form

So first equation, x-2y+8=0, now we subtract 8 on both sides aswell as subtract x and were left with -2y=-x-8 now we have to divide by negative two on both sides which gives you y=1/2x+4.

Then we do the same to the second equation. 2x+y+1=0. Se switch some things around and get Y=-2x-1

Okay so your answer would be something like this.

These lines are perpendicular since the slopes are the inverse of one another. The second like would run in the direction of the 4 quadrant. And the first in the direction of the 1st quadrant.

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48 = 2(2w)+(4+2w)2. What Is w

crimeas [40]

Hello from MrBillDoesMath!

Answer:

w = 5

Discussion:

48 = 2 (2w) + (4 + 2w)2 =>

48 = 4w + 4*2 + (2w)*2 =>

48 = 4w + 8 + 4w => as 4w + 4w = 8w

48 = 8w + 8 => subtracting 8 from each side

48 - 8 = 8w => divide both sides by 8

(48 -8 )/8 = w =>

40/8 = w =>

w = 5 =>

Check: 2(10) + ( 4 + 2*5)*2 = 20 + 14*2 = 20 + 28 = 48

Thank you,

MrB

6 0

2 years ago

-7n - 15 - 4n + (7) simplify the expression by combining like terms. help please?

SVEN [57.7K]

-7n-4n= -11n

-15+7= -8

-11n-8

6 0

3 years ago

Read 2 more answers

Need help with this problem.

tigry1 [53]

Answer:

C) $-\frac{47}{49}$

Step-by-step explanation:

By the cos double angle formula, we know $\cos(2\theta)=2\cos^2\theta-1.$ Substituting $\cos \theta$ into the formula, we get

$\cos(2\theta)=2(-\frac{1}{7})^2-1\\~~~~~~~~~~=\frac{2}{49}-1\\~~~~~~~~~~=\boxed{-\frac{47}{49}}$ .

The answer is C.

5 0

2 years ago

Find the volume of the figure. Use 3.14 for pi

Natasha2012 [34]

Answer:

Step-by-step explanation:

6 0

2 years ago

A man travels 20 km by car from Town P to Town Q at an average speed of x km/h. He finds that the time of the journey would be s

yuradex [85]

Answer:

x = 20.

Step-by-step explanation:

First, you should remember the relation:

Distance = Speed*Time.

First, we know that a man travels a distance of 20km at a speed of x km/h, in a time T.

We can write this as:

20km = (x km/h)*T

We know that the time is shortened by 12 minutes if the speed is increased by 5km/h

Rewriting these 12 minutes in hours (remember that 60min = 1 hour)

12 min = (12/60) hours = 0.2 hours

Then from this, he can travel the same distance of 20km in a time T minus 0.2 hours if the speed is increased by 5 km/h

We can write this as:

20km = (x + 5 km/h)*(T - 0.2 h)

Then we have a system of two equations, and we want to find the value of x:

20km = (x km/h)*T

20km = (x + 5 km/h)*(T - 0.2 h)

First, we should isolate the variable T in one of the equations, if we isolate it in the first one, we will get:

20km/(x km/h) = T

Replacing that in the other equation we get:

20km = (x + 5 km/h)*(T - 0.2 h)

20km = (x + 5 km/h)*( 20km/(x km/h) - 0.2 h)

Now we can solve this for x.

Removing the units (that we know that are correct) so the math is easier to read, we get:

20 = (x + 5)*(20/x - 0.2)

We only want to solve this for x.

20 = x*20/x - x*0.2 + 5*20/x - 5*0.2

20 = 20 - 0.2*x + 100/x - 1

subtracting 20 in both sides we get:

20 - 20 = 20 - 0.2*x + 100/x - 1 - 20

0 = -0.2*x + 100/x - 1

If we multiply both sides by x we get:

0 = -0.2*x^2 + 100 - x

-0.2*x^2 - x + 100 = 0

This is just a quadratic equation, we can solve it using the Bhaskara's equation, the solutions are:

$x = \frac{-(-1) \pm \sqrt{(-1)^2 - 4*(-0.2)*100} }{2*-0.2} = \frac{1 \pm 9 }{-0.4}$

Then the two solutions are:

x = (1 + 9)/-0.4 = -25

x = (1 - 9)/-0.4 = 20

As x is used to represent a speed, the negative solution does not make sense, so we should use the positive one.

x = 20

then the average speed initially is 20 km/h

3 0

2 years ago