x² + x = 3
Multiply the coefficient of x, which is by , getting .
Now square , getting =
Add + to both sides of the equation:
x² + x + = 3 +
The left side will now factor as (x + )(x + ) or (x + )². So we have:
(x + )² = 3 +
We will combine the terms on the right by getting the LCD of 16.
Then 3 + becomes + or .
So we now have:
(x + )² =
Next we use the principle of square roots:
x + = ±
x + = ±
Solve for x by adding to both sides:
x = ±
or you can write it:
x =
Edwin