When using substitution to solve this system of equations, what is the result of
the first step?
a) 2x + 3(x + 1) = 4
b) 2(x+1)+ 3y = 4
c) 2x + 3x + 1 = 4
d) 2x + 3y(x + 1) = 4
y = x + 1
2x + 3y = 4