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My name is Ann [436]
3 years ago
12

How do you solve system of eqautions using substitution

Mathematics
1 answer:
Licemer1 [7]3 years ago
8 0
Well basically you are plugging in variables. Lets use a random but simple system of equations.
y = 2x - 3
6x + 8y = 20
Now you need to plug in the top equation, which equals y, into the bottom equation.
6x + 8(2x - 3) = 20
6x + 16x - 24 = 20
Combine like terms.
22x - 24 = 20
Add 24 to both sides.
22x = 44
Divide.
x = 2
Now plug in 2 in any of the original equations.
y = 2x - 3
y = 2(2) - 3
y = 4 - 3
y = 1
So your solution is (2,1). And thats how you use substitution.
I hope this helps love! :)
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3 years ago
Read 2 more answers
WILL MARK BRAINLIEST <br><br> what is the domain of (f/g) (x)?
tatyana61 [14]

Given that f(x) = \sqrt{7-x} and g(x) = \sqrt{x + 2}, we can say the following:

\Bigg(\dfrac{f}{g}\Bigg)(x) = \dfrac{f (x)}{g(x)} = \dfrac{\sqrt{7 - x}}{\sqrt{x+2}}


Now, remember what happens if we have a negative square root: it becomes an imaginary number. We don't want this, so we want to make sure whatever is under a square root is greater than 0 (given we are talking about real numbers only).


Thus, let's set what is under both square roots to be greater than 0:

\sqrt{7 - x} \Rightarrow 7 - x \geq 0 \Rightarrow x \leq 7

\sqrt{x + 2} \Rightarrow x + 2 \geq 0 \Rightarrow x \geq -2


Since both of the square roots are in the same function, we want to take the union of the domains of the individual square roots to find the domain of the overall function.

x \leq 7 \,\,\cup x \geq -2 = \boxed{-2 \leq x \leq 7}


Now, let's look back at the function entirely, which is:

\Bigg( \dfrac{f}{g} \Bigg)(x) = \dfrac{\sqrt{7 - x}}{\sqrt{x+2}}

Since \sqrt{x + 2} is on the bottom of the fraction, we must say that \sqrt{x + 2} \neq 0, since the denominator can't equal 0. Thus, we must exclude \sqrt{x + 2} = 0 \Rightarrow x + 2 = 0 \Rightarrow x = -2 from the domain.


Thus, our answer is Choice C, or \boxed{ \{ x | -2 < x \leq 7 \}}.


<em>If you are wondering why the choices begin with the x | symbol, it is because this is a way of representing that x lies within a particular set.</em>

6 0
3 years ago
Find SY and XY. PLEASE HELP ME IT IS DUE SOON IF YOU DONT KNOW DO NOT ANSWER
alina1380 [7]

Answer:

SY = 16

XY = 12

Step-by-step explanation:

15/20 = 12/SY

15SY = 240

SY = 16

15/20 = 9/XY

15XY = 180

XY = 12

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Answer:  The mean increases.

Step-by-step explanation:

The value of 0.9 mg/L is very low compared to a means of 7.6 mg/L with a standard deviation of 2.1 mg/L.  It seems as though it is an outlier that is suffiently different from the others, and probably should be dropped from the data set.  That would do 2 things:  1) the stabdard deviation will likely decrease, indicating a more confident data set, and 2) the mean vitamin C level will increase.

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