Question

y= 2x – 15y = 5x Solve the system by using the substitution method

Answer 1

Substituting the second equation in the first one, we get:

$5x=2x-15.$

Subtracting 2x from the above equation we get:

$\begin{gathered} 5x-2x=2x-15-2x, \\ 3x=-15. \end{gathered}$

Dividing by 3, we get:

$\begin{gathered} \frac{3x}{3}=-\frac{15}{3}, \\ x=-5. \end{gathered}$

Substituting the above result in the second equation of the system, we get:

$\begin{gathered} y=5\cdot(-5), \\ y=-25. \end{gathered}$

Answer:

$\begin{gathered} x=-5, \\ y=-25. \end{gathered}$