Question

The difference between the root of the quadratic equation x^2-10x+ q=0 is 6. Find q.

Answer 1

Explanation:

Let A and B be the roots of the equation

x^2 - 10x + q = 0

A + B = -b/a and AB = c/a ( for the equation ax^2 + bx + c = 0).

So:-

A + B = 10

A - B = 6 (given)

Adding the 2 above equations:

2A = 16

A = 8.

so B = 10-8 = 2.

Now AB = q (as AB = c/a)

so q = 8*2 = 16.