Given the equation system:
[tex]\begin{gathered} 1)y=4x \\ 2)3x+2y=55 \end{gathered}[/tex]
The first step is to replace the first equation in the second equation
[tex]3x+2(4x)=55[/tex]
With this, we have a one unknown equation. Now we can calculate the value of x:
[tex]\begin{gathered} 3x+8x=55 \\ 11x=55 \\ \frac{11x}{11}=\frac{55}{11} \\ x=5 \end{gathered}[/tex]
Now that we know the value of x, we can determine the value of y, by replacing x=5 in the first equation
[tex]\begin{gathered} y=4x \\ y=4\cdot5 \\ y=20 \end{gathered}[/tex]
This system has only one solution and that is (5,20)
