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3 years ago

Y=4x and 3x+y=-21. Substitute

Mathematics

1 answer:

gizmo_the_mogwai [7]3 years ago

5 0

value of x= -3 and value of y = -12

Solution set is (-3,-12)

Step-by-step explanation:

We need to solve the system of equations using substitution

The system of equations are:

$y=4x\\3x+y=-21$

Solving:

Let

$y=4x\,\,eq(1)\\3x+y=-21\,\,eq(2)$

Solving:

Putting value of y from equation 1 into equation 2

$3x+y=-21\\3x+4x=-21\\7x=-21\\x=-21/7\\x=-3$

So, value of x = -3

Now, putting value of x into equation 1 and find value of y

$y=4x\\y=4(-3)\\y=-12$

Value of y = -12

So, value of x= -3 and value of y = -12

Solution set is (-3,-12)

Keywords: System of equations

Learn more about system of equations at:

#learnwithBrainly

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Malliki Williams earned a $48,000 from royalties on her cookbook.She paid a 28% income tax on these royalties. The balance wasin

Nikitich [7]

Answer:

$20000 and $14560

Step-by-step explanation:

First, we need to get the total tax paid by Malliki Williams

To get that, we have to multiply her income tax (28%) by total royalties ($48000)

28% of $48000 = $13440

Balance after tax = $48000 - $13440

Balance = $34560

She invested some of the balance ($34560) at the rate of

3.25% ---- First investment

1.75% --- Second investment

Assume her first investment is x dollars

Definitely, her second investment would be $34560 - x

3.25% of x + 1.75% (34560 - x ) = 904.8

0.0325x + 0.0175(34560-x) = 904.8 ----- Open the bracket

0.0325x + 604.8x - 0.0175x = 904.8 ------ Collect like terms

0.0325x -0.0175x =904.8 - 604.8

0.015x = 300 ------ Divide both sides by 0.015

x = 300/0.015

x = 20000

Remember that x represents her first investment

Her second investment is $34560 - $20000 =$14560

4 0

3 years ago

For every 140 feet that Kelly rides on her bicycle, the wheels turn 20 times. About how many times do the wheels turn in 5 miles

Mars2501 [29]

Answer: The wheels turn about 3771 times in 5 miles.

Step-by-step explanation:

Given, Kelly rides on her bicycle such that the number of times wheels turn for every 140 feet = 20

Turns for every feet = $\dfrac{20}{140}=\dfrac{1}{7}$ ...(i)

To find : Number of times wheels turn in 5 miles.

Since , 1 mile = 5,280 feet

Then, 5 miles = 5 x (5,280 feet) = 26,400 feet

Now , Number of times the wheels turn in 26,400 feet = 26400 x (Turns for every feet)

$26400\times\dfrac{1}{7}=3771.42857143\approx3771$ [From (i)

Hence, the wheels turn about 3771 times in 5 miles.

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