If x-y=7
A= 5(x-2y)-2(x-3y)-(-y-9)
You asked:
Solve the system of equations:\[\begin{aligned}x - y &= 7\\A &= 5 \cdot \left(x - 2 y\right) - 2 \cdot \left(x - 3 y\right) - \left(-y - 9\right)\end{aligned}\]
MathBot Answer:
The system of equations has infinitely many solutions.
$$\begin{aligned}A &= 30\\x &= y + 7\end{aligned}$$
\(y\) is a free variable.