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3 years ago

Use substitution to solve the following system of equations. - 4y - 5x = 30 AND x= y + 3

Mathematics

1 answer:

IRISSAK [1]3 years ago

3 0

Answer:

The solution to the system of equations is y = -5 and x = -2.

Step-by-step explanation:

The question tells us to use substitution to solve the system. This means that the given value for x (in terms of y) should be substituted into the other equation. This is modeled below:

-4y - 5x = 30

-4y - 5(y+3) = 30

Next, we should use the distributive property to simplify the left side of the equation.

-4y -5y - 15 = 30

The next step is to combine like terms on the left side of the equation.

-9y - 15 = 30

Then, we can add 15 to both sides of the equation.

-9y = 45

Finally, we can divide both sides of the equation by -9.

y = -5

To find the value for x, we substitute in the value we just found for y into either of our original equations.

x = y + 3

x = -5 + 3

x = -2

Therefore, the correct answer is y = -5 and x = -2.

Hope this helps!

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The inequality is used to solve how many hours of television Julia can still watch this week is $x + 1.5 \leq 5$

The remaining hours of TV Julia can watch this week can be expressed is 3.5 hours

<h3><u>Solution:</u></h3>

Given that Julia is allowed to watch no more than 5 hours of television a week

So far this week, she has watched 1.5 hours

To find: number of hours Julia can still watch this week

<em>Let "x" be the number of hours Julia can still watch television this week</em>

"no more than 5" means less than or equal to 5 ( ≤ 5 )

Juila has already watched 1.5 hours. So we can add 1.5 hours and number of hours Julia can still watch television this week which is less than or equal to 5 hours

number of hours Julia can still watch television this week + already watched ≤ Total hours Juila can watch

$x + 1.5 \leq5$

Thus the above inequality is used to solve how many hours of television Julia can still watch this week.

Solving the inequality,

$x + 1.5 \leq5\\\\x \leq 5 - 1.5\\\\x \leq 3.5$

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