quadratic equation

Question

with the roots being -6 and 2 and the leading coefficient is 4

Answer 1

 

f(x) = ax² + bx + c  with a = 4

 

-6 = [-b-√b² - 16c ] / 8 -----> b - 48 = -√b² -16c

 

4  = [-b+√b² - 16c ] / 8 -----> b + 32 =√b² -16c

 

2b -16 = 0 -----> b = 8

 

1600 = 64 - 16c ------> 100 = 8  -c ----> c = -92

 

f(x) = 4x² + 8x - 92