Respuesta :
Answer:
Step-by-step explanation:
A=4, B=-8, C=15
the discriminant B^2 - 4ac = (-8)^2 - 4(4)(15)
= 64 - 16(15)
= 64 - 240
= -176
= -1 * 11 * 4 * 4
Since this discriminant is negative, there are two imaginary/complex solutions.
the square root of this discriminant is 4 i sqrt(11)
the two solutions are [8 +or- 4 i sqrt(11)]/8
= [2 +or- i sqrt(11)]/2
check:
__________________________________________
it will suffice to show 4x^2 - 8x = -15....
x^2 = [2 + i sqrt(11)]/4 = [4 + 4 i sqrt(11) - 11]/4
= [4 i sqrt(11) - 7]/4
then 4x^2 = 4 i sqrt(11) - 7 <--- 4 cancels
and 8x = 4(2 + i sqrt(11) ) <-- 8 cancels 2
= 8 + 4 i sqrt(11)
So 4x^2- 8x = 4 i sqrt(11) - 7 - [ 8 + 4 i sqrt(11)]
= 4 i sqrt(11) - 7 - 8 - 4 i sqrt(11)
= -15
which is sufficient to show that the answer is correct.
the two solutions are [2 +or- i sqrt(11)]/2
are the official answers
