412,959 views
17 votes
17 votes
Solve the system using the substitution method. (If there is no solution, enter NO SOLUTION.)3x + 2y = 15x = y + 15(x, y) =

User Donny Rozendal
by
3.0k points

1 Answer

18 votes
18 votes

We hahve to solve the following system of equations:


\begin{gathered} 3x+2y=15 \\ x=y+15 \end{gathered}

We can use the second equation to replace x in the first equation and solve for y as:


\begin{gathered} 3x+2y=15 \\ 3(y+15)+2y=15 \\ 3y+45+2y=15 \\ 5y=15-45 \\ 5y=-30 \\ y=(-30)/(5) \\ y=-6 \end{gathered}

Knowing y we can calculate x as:


\begin{gathered} x=y+15 \\ x=-6+15 \\ x=9 \end{gathered}

Answer: (x,y) = (9,-6)

User Dave Novo
by
2.5k points