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3 years ago

7

If you were to use the substitution method to solve the following system, choose the new equation after the expression equivalen

t to x from the second equation is substituted into the first equation.
2x − 3y = −29
x + 4y = 13

A) 2(4y + 13) − 3y = −29
B) 2(−4y + 13) − 3y = −29
C) 2x − 3(4y + 13) = −29
D) 2x − 3(−4y + 13) = −29

1 answer:

Savatey [412]3 years ago

4 0

I’m pretty sure it’s A

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We're looking for a solution of the form $F(x,y)=C$ . By the chain rule, this solution should have total differential

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3 years ago

A motorboat maintained a constant speed of 15 miles per hour related to water going 44 miles upstream then returning the total t

yanalaym [24]

The speed of the current is 13 mph

<h3>What is speed?</h3>

speed refers to distance travelled per unit time. This is a vector quantity this implies that it has magnitude and direction.

The unit for speed as used here is miles per hour and can be written in short form as mph

<u>Given data</u>

speed of boat = 15 miles per hour = 15 mph

distance = 44 miles upstream

total time for the trip = 7.5 hours

<h3>solving for the speed of the current</h3>

let the water current be x

speed = distance / time

the total travel time upstream and downstream is known

for upstream

15 - x = 44 / time

time = 44 / 15 - x

for downstream

15 + x = 44 / time

time = 44 / 15 + x

total time = time for upstream + time for downstream = 7.5

7.5 = (44 / 15 - x ) + ( 44 / 15 + x )

7.5 = ( 44 ( 15 + x ) + 44 ( 15 - x ) ) / ( 15 + x )( 15 - x )

7.5 ( 15 + x )( 15 - x ) = 210 +44x + 210 - 44x

7.5 ( 225 - x ^ 2 ) = 420

( 225 - x ^ 2 ) = 56

169 = x ^ 2

x = sqrt ( 169 )

x = 13 miles per hour

hence speed of current is 13 miles per hour

Read more on speed here: brainly.com/question/4931057

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1 year ago

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This number is natural, whole, integer, and rational.

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6 0

3 years ago

Read 2 more answers

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Answer:

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Step-by-step explanation:

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We put equation 3 into equation 2 to get;

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We expand the bracket to get;

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3 years ago

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IgorC [24]

Set the equation to 125.

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3 years ago