Answer:
6
Explanation:
To start, the right side must be 0. Subtract 57 from both sides to get 2x² + 13x - 57 = 0. To use the quadratic equation, which is -b ± √b² - 4ac over 2a, plug in the numbers.
a = 2; b = 13; c = -57
The equation is then -13 ± √169 - 4(2)(-57) over 2. This simplifies to -13 ± √169 + 456 over 2, or -13 ± √625 over 2. The square root of 625 is 25, it becomes: -13 ± 25 over 2. -13 + 25, or 25 - 13, is 12. 12/2 is 6. Hope this helps! Have a great day! :)