Which of the following uses the substitution method to solve the system y = x^2 - 4x + 8, y = 3x - 4?
The substitution method involves solving one equation for a variable and substituting it into the other equation. In this case, we can solve the second equation for y and substitute it into the first equation.
First, solve the second equation for y:
y = 3x - 4
Now substitute this expression for y into the first equation:
3x - 4 = x^2 - 4x + 8
This equation is now a quadratic equation. The other equation, y = 3x - 4 is not needed anymore. So the system that uses the substitution method to solve is:
3x - 4 = x^2 - 4x + 8