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3 years ago

Solve system by elimination -9x - y =-19 5x + y = 15

Mathematics

1 answer:

vredina [299]3 years ago

6 0

Answer:

(1, 10 )

Step-by-step explanation:

Given the 2 equations

- 9x - y = - 19 → (1)

5x + y = 15 → (2)

Adding the 2 equations term by term will eliminate the y- term

- 4x + 0 = - 4

- 4x = - 4 ( divide both sides by - 4 )

x = 1

Substitute x = 1 into either of the 2 equations and solve for y

Substituting into (2)

5(1) + y = 15

5 + y = 15 ( subtract 5 from both sides )

y = 10

solution is (1, 10 )

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3 years ago

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3 years ago

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Check the picture below.

so, the center of the circle is the midpoint of that diametrical segment, and half that length is the radius.

$\bf ~~~~~~~~~~~~\textit{middle point of 2 points }
\\\\
\begin{array}{ccccccccc}
&&x_1&&y_1&&x_2&&y_2\\
% (a,b)
&&(~ -2 &,& -4~) 
% (c,d)
&&(~ 3 &,& 8~)
\end{array}\qquad
% coordinates of midpoint 
\left(\cfrac{ x_2 + x_1}{2}\quad ,\quad \cfrac{ y_2 + y_1}{2} \right)
\\\\\\
\left( \cfrac{3-2}{2}~~,~~\cfrac{8-4}{2} \right)\implies \left( \frac{1}{2}~,~2 \right)\impliedby center$

$\bf ~~~~~~~~~~~~\textit{distance between 2 points}
\\\\
\begin{array}{ccccccccc}
&&x_1&&y_1&&x_2&&y_2\\
% (a,b)
&&(~ -2 &,& -4~) 
% (c,d)
&&(~ 3 &,& 8~)
\end{array}~~~ 
% distance value
d = \sqrt{( x_2- x_1)^2 + ( y_2- y_1)^2}
\\\\\\
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\\\\\\
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$\bf \textit{equation of a circle}\\\\ 
(x- h)^2+(y- k)^2= r^2
\qquad 
center~~(\stackrel{\frac{1}{2}}{ h},\stackrel{2}{ k})\qquad \qquad 
radius=\stackrel{\frac{13}{2}}{ r}
\\\\\\
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3 years ago

Read 2 more answers