Final answer:
To find the value of b and the other solution of the quadratic equation 40x² + bx - 9 = 0, you can substitute the given solution x = -(9/5) and solve for b. The quadratic formula can then be used to find the other solution.
Step-by-step explanation:
This expression is a quadratic equation of the form at² + bt + c = 0, where the constants are a = 40, b = b, and c = -9. The given solution is x = -(9/5). To find the value of b, we can substitute the values into the quadratic equation and solve for b. The other solution can be found using the quadratic formula.