To find the solutions to the quadratic equation 3x² + 42x + 75 = 0, we can use the quadratic formula, which is given by:
x = (-b ± √(b² – 4ac)) / 2a
In this equation, the coefficients are:
- a = 3
- b = 42
- c = 75
First, we need to calculate the discriminant (b² – 4ac):
1. Calculate b²:
42² = 1764
2. Calculate 4ac:
4 * 3 * 75 = 900
3. Now, calculate the discriminant:
b² – 4ac = 1764 – 900 = 864
Since the discriminant is positive, we can expect two real solutions. Now we can plug in the values into the quadratic formula:
x = (-42 ± √864) / (2 * 3)
First, we simplify:
√864 can be simplified to √(144 × 6) = 12√6.
Now, substitute that back into our equation:
x = (-42 ± 12√6) / 6
This simplifies to:
x = -7 ± 2√6
Thus, the two solutions to the quadratic equation 3x² + 42x + 75 = 0 are:
- x = -7 + 2√6
- x = -7 – 2√6
In decimal form, these approximate to:
- x ≈ -3.898
- x ≈ -10.102
So the complete solution set is { -7 + 2√6, -7 – 2√6 }.