How do you solve the system y=x-1 and x+y =3?

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Answer 1 · 2018-03-03T05:37:51

Since only one of the variables is defined, we can use the substitution method so first, substitute for y
$x + (x - 1) = 3$ $x+(x-1)=3$

Then, combine like terms and solve for x
$2 x - 1 = 3$ $2x-1=3$
$x = 2$ $x=2$

Now that we know what x is, we can substitute for x in the other equation to find y
$y = 2 - 1$ $y=2-1$
$y = 1$ $y=1$

Now that we know what both x and y are, we can substitute for the variables
$1 = 2 - 1$ $1=2-1$ (correct)
$2 + 1 = 3$ $2+1=3$ (correct)

We can now conclude the answer
$(2, 1)$ $(2,1)$