A system of equations is given below:

y = 4x - 3

2x + 7y = 41

Which of the following steps could be used to solve by substitution?

2 (y = 4x - 3) + 7y = 41

4x - 3 = 2x + 7y

2x + 7 (4x - 3) = 41

2 (y = 4x - 3)

The given system of equations is:

y = 4x - 3 ... (1)

2x + 7y = 41 ... (2)

Notice that the first equation is a solved equation for y. So, we can simply substitute 4x-3 for y in equation (2) to solve. This method is also knwon as substitution method by which we can plug in one equation into other equation.

So, if we will substitute y=4x-3 in equation (2) then we will get,

2x+7 (4x-3) = 41

Hence, third choice 2x + 7 (4x - 3) = 41 is the correct answer.