Answer:
(-5, 2)
Step-by-step explanation:
Given system of equations:
[tex]\begin{cases}-2x-5y=20\\y=\dfrac{4}{5}x+2\end{cases}[/tex]
Both equations are linear equations.
Equation 1
Rearrange Equation 1 to make y the subject:
[tex]\implies -2x-5y=20[/tex]
[tex]\implies -5y=2x+20[/tex]
[tex]\implies y=-\dfrac{2}{5}x-4[/tex]
Therefore, the graph of this equation is a straight line with a negative slope and a y-intercept of (0, -4).
Find two points on the line by substituting two values of x into the equation:
[tex]x = 0\implies y=-\dfrac{2}{5}(0)-4=-4 \implies (0,-4)[/tex]
[tex]x = 5 \implies y=-\dfrac{2}{5}(5)-4=-6 \implies (5,-6)[/tex]
Plot the found points and draw a straight line through them.
Equation 2
The graph of this equation is a straight line with a positive slope and a y-intercept of (0, 2).
Find two points on the line by substituting two values of x into the equation:
[tex]x = 0 \implies y=\dfrac{4}{5}(0)+2=2 \implies (0,2)[/tex]
[tex]x = 5 \implies y=\dfrac{4}{5}(5)+2=6 \implies (5,6)[/tex]
Plot the found points and draw a straight line through them.
Solution
The solution(s) to a system of equations is the point(s) of intersection.
From inspection of the graph, the point of intersection is (-5, -2).
To verify the solution, substitute the second equation into the first and solve for x:
[tex]\implies \dfrac{4}{5}x+2=-\dfrac{2}{5}x-4[/tex]
[tex]\implies \dfrac{6}{5}x=-6[/tex]
[tex]\implies 6x=-30[/tex]
[tex]\implies x=-5[/tex]
Substitute the found value of x into one of the equations and solve for y:
[tex]\implies \dfrac{4}{5}(-5)+2=-2[/tex]
Hence verifying that (-5, -2) is the solution to the given system of equations.
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