ABSTRACT
We can substitute for y in the second equation, noting that the first equation gives us y = 7 − x. So, we have x(7 − x) = 3, or 7x – x2 = 3. is gives us the quadratic equation
x2 – 7x + 3 = 0.
Now it’s smooth sailing. We just bring in the quadratic formula,
x = ± − = ±7 7 4 3 1 2
7 37 2
2 ( )( ) .
