Final answer:
To solve the system by substitution, we need to solve one equation for one variable and then substitute that expression into the other equation. The solution to the system of equations is x = 3.9 and y = -9.1.
Step-by-step explanation:
To solve the system by substitution, we need to solve one equation for one variable and then substitute that expression into the other equation. Let's solve the second equation for y:
y = -7x/3
Now substitute this expression for y into the first equation:
x - (-7x/3) = 13
Multiplying both sides by 3 gives:
3x + 7x = 39
Combining like terms:
10x = 39
Dividing both sides by 10:
x = 3.9
Now substitute this value of x back into the expression for y:
y = -7(3.9)/3
Calculating:
y = -27.3/3 = -9.1
Therefore, the solution to the system of equations is x = 3.9 and y = -9.1.