9 + - 24
a positive and negative make a negative, so the question is actually
9 - 24 which is -15
Please add a photo so we can understand what you mean and your question.
Answer:
Fourth option: x=1±√47
Step-by-step explanation:
This is a quadratic equation, then we must equal to zero: Subtracting both sides of the equation x², 5x, and 39:
![2x^{2}+3x-7-x^{2}-5x-39=x^{2}+5x+39-x^{2}-5x-39](https://tex.z-dn.net/?f=2x%5E%7B2%7D%2B3x-7-x%5E%7B2%7D-5x-39%3Dx%5E%7B2%7D%2B5x%2B39-x%5E%7B2%7D-5x-39)
Subtracting like terms:
![x^{2}-2x-46=0](https://tex.z-dn.net/?f=x%5E%7B2%7D-2x-46%3D0)
Applying the quadratic formula:
![ax^{2}+bx+c=0; a=1, b=-2, c=-46](https://tex.z-dn.net/?f=ax%5E%7B2%7D%2Bbx%2Bc%3D0%3B%20a%3D1%2C%20b%3D-2%2C%20c%3D-46)
![x=\frac{-b+-\sqrt{b^{2}-4ac}}{2a}\\ x=\frac{-(-2)+-\sqrt{(-2)^{2}-4(1)(-46)}}{2(1)}\\ x=\frac{2+-\sqrt{4+184}}{2}\\ x=\frac{2+-\sqrt{188}}{2}\\ x=\frac{2+-\sqrt{4(47)}}{2}\\ x=\frac{2+-\sqrt{4}\sqrt{47}}{2}\\ x=\frac{2+-2\sqrt{47}}{2}\\ x=\frac{2}{2}+- \frac{2\sqrt{47}}{2}\\ x=1+-\sqrt{47}](https://tex.z-dn.net/?f=x%3D%5Cfrac%7B-b%2B-%5Csqrt%7Bb%5E%7B2%7D-4ac%7D%7D%7B2a%7D%5C%5C%20x%3D%5Cfrac%7B-%28-2%29%2B-%5Csqrt%7B%28-2%29%5E%7B2%7D-4%281%29%28-46%29%7D%7D%7B2%281%29%7D%5C%5C%20x%3D%5Cfrac%7B2%2B-%5Csqrt%7B4%2B184%7D%7D%7B2%7D%5C%5C%20x%3D%5Cfrac%7B2%2B-%5Csqrt%7B188%7D%7D%7B2%7D%5C%5C%20x%3D%5Cfrac%7B2%2B-%5Csqrt%7B4%2847%29%7D%7D%7B2%7D%5C%5C%20x%3D%5Cfrac%7B2%2B-%5Csqrt%7B4%7D%5Csqrt%7B47%7D%7D%7B2%7D%5C%5C%20x%3D%5Cfrac%7B2%2B-2%5Csqrt%7B47%7D%7D%7B2%7D%5C%5C%20x%3D%5Cfrac%7B2%7D%7B2%7D%2B-%20%5Cfrac%7B2%5Csqrt%7B47%7D%7D%7B2%7D%5C%5C%20x%3D1%2B-%5Csqrt%7B47%7D)
After 500 trials, she should expect 0.16 * 500, or 80 red marbles. 0.16 is the frequency of red (8/50). If you extend this expected frequency to 500 trials, it will be 80.
164*.047 is 7.708 rounded to the nearest cent its $7.71