# For which of the following equations are x = 5 and x = –5 both solutions?,

(a).x^{2} + 25

(b).x^{2} - 10

(c).x^{2} - 25

(d).x^{2} + 10

We will use the concept of a quadratic equation to find the required equation.

## Answer: Here x = 5, and x = -5 are both solutions of the equation (c) x^{2}-25

Let us understand the solution with the help of the following explanation.

**Explanation:**

The given two solutions are x = 5, and x = -5.

This can be written as x - 5 = 0, and x + 5 = 0.

Further combining these two we have (x - 5)(x + 5) = 0.

Finally we have (x - 5)(x + 5) = x^{2} - 25.

Hence, for the solutions x = 5 and x = –5, we have the equation x^{2} - 25.