Question 149175
First, you have to know the rule that the number of unknowns
(x,y,z,etc.) has to match the number of equations, and in
your problem, it does (2 equations and 2 unknowns), so this
system is solvable
Is the first equation {{{y = -1}}}? If so,
just substitute this value in the 2nd equation
{{{3x + y = 5}}}
{{{3x +(-1) = 5}}}
{{{3x - 1 = 5}}}
add 1 to both sides
{{{3x = 6}}}
Divide both sides by 3
{{{x = 2}}}
The solutions are y = -1 and x = 2