Thread: Roots of the Equation

The roots of the equation

ax^2 + 4x = –2 are real, rational, and equal when a has a value of

(1) 1 (3) 3
(2) 2 (4) 4

Originally Posted by magentarita

The roots of the equation

ax^2 + 4x = –2 are real, rational, and equal when a has a value of

(1) 1 (3) 3
(2) 2 (4) 4

If a=1, then has irrational roots. (Use quadratic formula)

If a=2, then . Dividing all terms by 2, we have:

. Now factor to get:

. We have 2 equal roots (double root) at x=-1

If you test a=3 and a-4, you'll see that they have imaginary roots.

Originally Posted by masters

If a=1, then has irrational roots. (Use quadratic formula)

If a=2, then . Dividing all terms by 2, we have:

. Now factor to get:

. We have 2 equal roots (double root) at x=-1

If you test a=3 and a-4, you'll see that they have imaginary roots.

A wonderful repy as always.