1. Given the polynomial equation:
4x4−3x2+7x−3=0
we need to find the sum of the real roots.
2. We start by using synthetic division to check for possible rational roots. Let's test x=21:
Synthetic division of 4x4−3x2+7x−3 by (2x−1):
2x−14402−3−176−30
The remainder is 0, so x=21 is a root, and 4x4−3x2+7x−3 can be factored as:
4x4−3x2+7x−3=(2x−1)(2x3+x2−x+3)
3. Next, we apply synthetic division again to the cubic polynomial 2x3+x2−x+3 to check for another rational root. Let's test x=−23:
Synthetic division of 2x3+x2−x+3 by (2x+3):
2x+3221−2−1230
The remainder is 0, so x=−23 is a root, and 2x3+x2−x+3 can be factored as:
2x3+x2−x+3=(2x+3)(x2−x+1)
4. Now, we have:
4x4−3x2+7x−3=(2x−1)(2x+3)(x2−x+1)
5. The quadratic x2−x+1 has no real roots because its discriminant is negative:
Δ=(−1)2−4⋅1⋅1=1−4=−3
6. Therefore, the only real roots of the original polynomial are x=21 and x=−23.
7. The sum of the real roots is:
21+(−23)=21−23=−1
The final answer is −1.