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andreev551 [17]

2 years ago

7

Please help me with this math word problem

1 answer:

hjlf2 years ago

3 0

Answer: The cost of 16 pencils and 10 notebooks is $5.84.

Explanation: You can solve this using linear systems:

Let X be the cost per pencil, and let Y be the cost per notebook.

(1) 7x+8y=4.15
(2) 5x+3y=1.77

Choose a variable to eliminate. I’ll eliminate X first as an example. To eliminate a variable, you must have the same coefficient beside the variable for both equations.

Equation 1 now becomes:

(3) 35x+40y=20.75

Equation 2 now becomes:

(4) 35x+21y=12.39

Now that you have 35 as a coefficient for X in both equations, you can subtract the two equations to officially eliminate it!

(3)-(4)

19y=8.36
y=0.44

Now that you have the value of Y, substitute that value into either one of the equations to get X.

Substitute y=0.44 in (1)

7x+8(0.44)=4.15
7x+3.52=4.15
7x=0.63
x=0.09

Therefore, the cost per pencil is $0.09/pencil and the cost per notebook is $0.44/notebook.

Almost done lol...

To find the cost of 16 pencils, multiply 0.09*16. That gives you $1.44, which will be the cost of 16 pencils.
The cost of 10 notebooks is 0.44*10, which gives you $4.40. That’s the cost of 10 notebooks.

To find the total price, add these values together!

1.44+4.40=5.84

Therefore, the cost of 16 pencils and 10 notebooks is $5.84.

Hope that helps シ

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Through: (-5, -3), perp. to y=-9/4x-5

Mrrafil [7]

Given:

A line passes through (-5,-3) and perpendicular to $y=-\dfrac{9}{4}x-5$ .

To find:

The equation of the line.

Solution:

We have,

$y=-\dfrac{9}{4}x-5$

On comparing this equation with slope intercept form, i.e., $y=mx+b$ , we get

$m_2=-\dfrac{9}{4}$

It means, slope of this line is $-\dfrac{9}{4}$ .

Product of slopes of two perpendicular lines is always -1.

$m_1\times m_2=-1$

$m_1 \times \left(-\dfrac{9}{4}\right)=-1$

$m_1=\dfrac{4}{9}$

Slope of required line is $\dfrac{4}{9}$ and it passes through the point (-5,-3). So, the equation of the line is

$y-y_1=m(x-x_1)$

where, m is slope.

$y-(-3)=\dfrac{4}{9}(x-(-5))$

$y+3=\dfrac{4}{9}(x+5)$

$9(y+3)=4(x+5)$

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8 0

3 years ago

Can someone answer this really fast?

Vikki [24]

Answer:

Use your brain

Step-by-step explanation:

Because

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3 years ago

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Kruka [31]

Answer:

The given system as (3,3) as its solution.

Step-by-step explanation:

Here, the given system of the equation is:

4 x + 2 y = 18 ................ (1)

2 x + 3 y = 15 ............... (2)

Now, to use the elimination method, w need to eliminate any of the variable.

Eliminate the variable x in the given system.

Multiply equation (2) with -2 we get,

(2 x + 3 y = 15 )(-2) ⇒ -4x - 6y = -30 ....... (3)

Add (1) and (3), we get:

4 x + 2 y -4x - 6y = 18 -30

or, - 4 y = - 12

or, y = 12/4 = 3 ⇒ y = 3

Putting in (1), we get

4x + 2(3) = 18 or, 4x = 18 - 6 = 12

or, x = 3

(x,y) = (3,3)

Hence, the above system as (3,3) as its solution.

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In order to ride a roller coaster,a rider must be greater than 49 inches tall.Right now,Jeff is 45 inches tall.Write an inequali

WARRIOR [948]

Answer:

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Step-by-step explanation:

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