Answer:
Solution 1:
![x = 5](https://img.qammunity.org/2022/formulas/mathematics/college/zl3xsuljtiu8wy0fz8ilueakk81qu6lhda.png)
Solution 2:
![x = -4](https://img.qammunity.org/2022/formulas/mathematics/high-school/s75mvvfsep316ix3e6orvljq9fp9c2vrbf.png)
Explanation:
The first is organize the given equation to the next form
![ax^2 + bx + c](https://img.qammunity.org/2022/formulas/mathematics/college/qb79ql5dggwtlcv6amm61xhvw1fhbd82fw.png)
So you substract -20 in both sides of the equation
Know you can use the quadratic formula or find two number that sum give us
and multiplied
.
![b = s + r\\c = sr](https://img.qammunity.org/2022/formulas/mathematics/college/44fzphljrn2ca7hncw7s26n6rxn318gidp.png)
Replacing with the given values we have:
![-1 = s + r\\-20 = sr](https://img.qammunity.org/2022/formulas/mathematics/college/pk5nhrno7y8lliqjxbhf7ptvjrafzs91ft.png)
With a trial and error the numbers are -5 and 4. Then you change the equation to
![x^2 - x - 20 = (x - 5)(x + 4)](https://img.qammunity.org/2022/formulas/mathematics/college/5auiix746r6d669vrecd5rwwjdqnggjyu9.png)
And the equation is equal to 0 when
is equal to 5 and -4.