Final answer:
To solve this system of equations using substitution, isolate one variable in one equation and substitute it into the other equation. The solution is x = -3 and y = -2.
Step-by-step explanation:
To solve this system of equations using substitution, you need to isolate one variable in one equation and substitute it into the other equation. Let's start with the first equation:
x - 5y = 7
Isolate x:
x = 7 + 5y
Now, substitute this value of x into the second equation:
2(7 + 5y) + 7y = -20
Simplify:
14 + 10y + 7y = -20
Combine like terms:
17y = -34
Divide both sides by 17:
y = -2
Substitute the value of y back into the first equation to find x:
x - 5(-2) = 7
Simplify:
x + 10 = 7
Subtract 10 from both sides:
x = -3
Therefore, the solution to the system of equations is x = -3 and y = -2.