For the polynomial z^2 - 3 z + 4 = 0, what is the sum of its roots?

Boost your skills in A Level Further Mathematics Core Pure. Study with flashcards and multiple choice questions, each question is followed by hints and explanations. Get prepared for your exam with confidence!

Multiple Choice

For the polynomial z^2 - 3 z + 4 = 0, what is the sum of its roots?

For a quadratic ax^2 + bx + c = 0, the sum of the roots is -b/a (that's Vieta's formula). Here the coefficient of z^2 is 1 and the coefficient of z is -3, so the sum is -(-3)/1 = 3. If you compute the roots explicitly, z = (3 ± i√7)/2, and adding them gives 3 as well. So the sum of the roots is 3.

For a quadratic ax^2 + bx + c = 0, the sum of the roots is -b/a (that's Vieta's formula). Here the coefficient of z^2 is 1 and the coefficient of z is -3, so the sum is -(-3)/1 = 3. If you compute the roots explicitly, z = (3 ± i√7)/2, and adding them gives 3 as well. So the sum of the roots is 3.

More practice questions