Now, try one on your own.
Solve using substitution:
x2 + y = 3 | The first equation | |
x2 + (3x + 5) = 3 | Substitute (3x + 5) for y | |
x2 + 3x + 5 – 3 = 3 – 3 | Substract 3 from both sides of the equation | |
x2 + 3x + 2 = 0 | Simplify | |
(x + 2)(x + 1) = 0 | Factor | |
x = -2 or | x = -1 | Solve each factor for x |
y = 3(-2) + 5 = -1 | y = 3(-1) + 5 = 2 | Substitute the x-values into the second equation to find y |
The solutions are (-2, -1) and (-1, 2) |
Now, write a journal entry in your notes describing the type(s) of situations in which substitution would be a more appropriate method than tables or graphs for solving a system of equations.