Answer: [tex](x,y) = (5,15)[/tex]
Step-by-step explanation:
When solving system of equations, substitution is one solid method to use. Substitution means, plugging in a variable's value in terms of another value to eliminate one variable and solve for the other.
Let me show you how to do that with this problem!
Solving:
Given : [tex]x+y = 20[/tex] and [tex]y=3x[/tex]
In order to use substitution, plug in 3x for the value of y in the original expression and solve.
Substitution :
[tex]x+(3x)=20[/tex]
[tex]4x=20[/tex]
[tex]x=5[/tex]
Now since [tex]y=3x[/tex] just mutliply the x-value by 3 to get the y-vaue:
[tex]y=3(5)[/tex]
[tex]y=15[/tex]
If you plug these solutions back into the original expression, it holds true!
That's it!
