4x + 10= 2x - 6
Subtract 2x on both sides
4x - 2x + 10 = 2x - 2x - 6
4x - 2x + 10 = -6
2x + 10 = -6
Subtract 10 on both sides
2x + 10 - 10 = -6 - 10
2x = -6 - 10
2x = -16
x = -8
The correct first step to solving the system of equations in the most efficient manner is x = -4y +19.
The given system of equations is;

<h2>What is the first step to solving an equation?</h2>
The first step would be to rearrange the variables in the second equation so we have a defined expression for x.
We would want to do this so we could then plug in the defined expression for x into the other equation and solve for the other variable.
x + 4y = 19
Rearrange this by getting the 4y to the other side.
We can get 4y on the other side by subtracting 4y from both sides
x + 4y - 4y = 19 - 4y
x = -4y + 19
Hence, the correct first step to solving the system of equations in the most efficient manner is x = -4y +19.
To know more about the System of equations click the link given below.
brainly.com/question/15240525
The second number of each ordered pair for g(x) is 2 less than that for f(x).
The value of k is -2.