Andrew M. answered 03/25/18
Tutor
New to Wyzant
Mathematics - Algebra a Specialty / F.I.T. Grad - B.S. w/Honors
2x2 - 5x + 7 = 0
Since this is not factorable use quadratic equation.
x = (-b ±√(b2-4ac))/2a with a=2, b=-5, c=7
x = [5±√((-5)2-4(2)(7))]/(2(2))
x = [5 ±√(25-56)]/4
x = (5 ± i√31)/4
a = (5+i√31)/4
b = (5-i√31)/4
2a = (5+i√31)/2
3b = (15 - 3i√31)/4
2a + 3b = (10 + 2i√31 + 15 - 3i√31)/4
= (25 -i√31)/4
= 25/4 - i√31/4
If 2a+3b is a zero then x - (2a+3b) is a factor
[x - (25 -i√31)/4] is a factor of p(x)
or
(x - 25/4 + i√31/4)
3a = (15+3i√31)/4
2b = (5-i√31)/2
3a + 2b = [15+3i√31+10-2i√31]/4
= (25 + i√31)/4
= 25/4 + (i√31)/4
Then: x - (3a+2b) =
(x - 25/4 - (i√31)/4) is a factor of p(x)
p(x) = (x - 25/4 + i√31/4)(x - 25/4 - (i√31)/4)
As you can see this is not going to multiply out nicely:
p(x) = x2 - (25/2)x + 189/4 - (25i√31)/8
Are you sure there isn't a mistake in the problem statement?