To solve the equation 5x² + 3x – 25 = 0 by completing the square, follow these steps:
- Divide the entire equation by 5:
This simplifies the equation to: x² + (3/5)x – 5 = 0 - Rearrange the equation:
Move the constant term to the other side:
x² + (3/5)x = 5 - Complete the square:
To do this, take half of the coefficient of x (which is 3/5), square it, and add this value to both sides of the equation.
Half of (3/5) is (3/10) and squaring it gives (9/100).
Now add (9/100) to both sides:
x² + (3/5)x + (9/100) = 5 + (9/100) - Simplify the equation:
The left side can be factored as:
(x + 3/10)² = 500/100 + 9/100 = 509/100 - Take the square root of both sides:
x + 3/10 = ±√(509/100) - Isolate x:
x = -3/10 ± √(509)/10
Thus, the solutions to the equation are:
- x = (-3 + √509) / 10
- x = (-3 – √509) / 10