If the sum of the roots of the quadratic equation 5x2 + bx + 4 = 0 is 9, then find the value of b.

Explanation

To find the value of b , let's use the information about the sum of the roots of a quadratic equation. Step 1: Recall the standard form of a quadratic equation, which is: ax² + bx + c = 0 For the given equation, 5x² + bx + 4 = 0 , we have: a=5 b = b (the value we need to find) c=4 Step 2: Use the formula for the sum of the roots of a quadratic equation, which is given by: Sum of roots = -b / a Step 3: Substitute the values we know: The sum of the roots is given as 9. Therefore, -b / 5 = 9 Step 4: Solve for b : -b = 9 * 5 -b = 45 b = -45 Answer: The value of b is -45.