Which of the following would be the best first step when solving the following system using the substitution method?
x - y = -4 ;
x + 2y = 5
a. x = -4 - y
b. x = -4 + y
c. 2y = 5 - x
d. 2y = 5 + x
To solve the given system of equations using the substitution method, we need to isolate one variable in one of the equations and substitute it into the other equation. This will allow us to solve for the values of the variables.
Let's examine the given system of equations:
x - y = -4 ----(Equation 1)
x + 2y = 5 ----(Equation 2)
To find the best first step, we should isolate one variable in one of the equations. Looking at Equation 1, we can easily isolate the variable x:
x = -4 + y
Therefore, the correct answer would be option b: x = -4 + y. This step allows us to express the value of x in terms of y.
After finding this substitution, we can substitute the expression for x in Equation 2:
(-4 + y) + 2y = 5
From here, we can simplify and solve for y.
add y to both sides of the top equation.
but
I would do it by elimination, subtract and x is gone.