The inequality 2 x 2 + 5 x < 3 can be analyzed using its discriminant to confirm it has two rational solutions. Tebogo scored approximately 86.15% in Assignment 3, making it her best performance. For the equation ( x + 1 ) 2 + 3 x = 0 , the solution set is given by two real roots based on the calculated discriminant.
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Let's tackle each part of the problem one by one.
Part 1: Solve the inequality 2 x 2 + 5 x < 3
Rearrange the inequality to standard form: 2 x 2 + 5 x − 3 < 0
Solve the quadratic equation 2 x 2 + 5 x − 3 = 0 :
To find if this quadratic equation has two rational solutions, use the discriminant b 2 − 4 a c , where a = 2 , b = 5 , and c = − 3 .
b 2 − 4 a c = 5 2 − 4 × 2 × ( − 3 ) = 25 + 24 = 49
Since the discriminant is a perfect square ( 49 ), it has two rational solutions.
Graphical solution of inequality:
The quadratic represents a parabola that opens upwards because 0"> a = 2 > 0 .
The solution to 2 x 2 + 5 x − 3 < 0 is the interval between the two roots found from solving 2 x 2 + 5 x = 3 .
Part 2: Find which assignment Tebogo performed the best in (percentage calculations):
Assignment 1: 75 64 × 100 ≈ 85.33%
Assignment 2: 80 62 × 100 = 77.5%
Assignment 3: 65 56 × 100 ≈ 86.15%
Tebogo performed the best in Assignment 3 with approximately 86.15%.
Part 3: Find the solution set of ( x + 1 ) 2 + 3 x = 0 :
Equation: ( x + 1 ) 2 + 3 x = 0
Remove the square root by squaring both sides: ( x + 1 ) 2 + 3 x = 0
Simplify and solve the quadratic equation: x 2 + 2 x + 1 + 3 x = 0 x 2 + 5 x + 1 = 0
Since the discriminant b 2 − 4 a c = 25 − 4 is not a perfect square, the equation has no real solutions.
Therefore, the solution set is empty as the expression under the square root cannot be negative.
By breaking down each part step-by-step, you can easily follow the logic and find the solutions to these mathematical problems.