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3 years ago

Assume y varies directly as x. If y = 30 when x = -3, find y when x = -9.

Mathematics

1 answer:

navik [9.2K]3 years ago

7 0

Answer:

y is 90

Step-by-step explanation:

The y/x is proportional per point (x,y) since this is a direct variation.

That is ,

$\frac{30}{-3}=\frac{y}{-9}$ .

Cross multiply:

$30(-9)=y(-3)$

Simplify:

$-270=-3y$

Divide both sides by -3

$\frac{-270}{-3}=y$

$90=y$

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Is this the right answer?

iren2701 [21]

Hello from MrBillDoesMath!

Answer:

Yes!

Discussion:

a + b= 2a => subtract "a" from both sides

a - a + b = 2a - a => as (a-a) = 0 and (2a-a) = a

b = a (*)

Then from (*) above

b-a = b - b => b-b = 0

b -a = 0

Thank you,

MrB

8 0

3 years ago

Find f(-2) if f(x) = 4x + 8

zzz [600]

Answer:

Step-by-step explanation:

Use the hint lol
Step 1: Plug in -2 into the equation.
f(-2) = 4(-2) + 8

Step 2: Multiply
f(-2) = -8 + 8

Step 3: Add

f(-2) = 0

5 0

2 years ago

Read 2 more answers

What is the equation of a circle with its center at (10,−4) and a radius of 2?

Dmitrij [34]

Equation of circle
(x-h)^2 + (y-k)^2 = r^2
=> (x-10)^2 + (y+4)^2 = 4 is the answer

7 0

3 years ago

A plan of a garden is shown below.

siniylev [52]

The length and width of the conservatory are both 4.5 meters

<h3>How to determine the length and the width?</h3>

From the figure, we have the following highlights:

Length = 3 units
Width = 3 units

A unit = 1.5 meters

So, we have:

Width = Length = 3 * 1.5 meters

Width = Length = 4.5 meters

Hence, the length and width of the conservatory are both 4.5 meters