One of the roots of the equation 4x ^ 2-x + c = 0 is equal to 1.25 which is equal to the second root.

We know that one of the roots of the equation 4×2 – x + c = 0 is 1.25. In order to find what the second root is, we will use Vieta’s theorem.

Let’s remember her.

The roots of the complete quadratic equation ax2 + bx + c = 0 satisfy the following equalities:

x1 + x2 = -b / a;

x1 * x2 = c / a.

Let’s write out the coefficients a and b from the given equation.

a = 4; b = -1;

We substitute Vieta’s theorem into the first equality and obtain the equation:

1.25 + x = 1/4;

1.25 + x = 0.25;

x = 0.25 – 1.25;

x = -1.

Answer: the second root of the equation is -1.