Question

What is the sum of the roots of the equation 2x2+5x−3=0?

Question 1 options:

-3.5


-2.5


-1.5


2.5

Answer 1

-2.5

Explanation:

For roots "a" and "b" a quadratic can be written as ...

(x -a)(x -b) = x^2 -(a+b)x +ab

Note that the coefficient of x is -(a+b), the opposite of the sum of the roots.

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If we divide your equation by 2, we can put it into the form above:

x^2 -(-5/2)x -3/2 = 0

This tells us the sum of the roots is -5/2 = -2.5.