Question

the value of x2-5 at x = -1 is​

Answer 1

Answer:

-4

Explanation:

substitute x=-1 in the given equation...

then,

(-1)^2-5

1-5

-4

Answer 2

Given:

• An equation $x^2-5$

To Find:

• To solve the given equation when x = -1

Solution:

Let us equate the given equation to zero, we get

⇒ $x^2-5=0$

On substituting the value of "x" in the above equation we get,

⇒$x^2-5$ =  $(-1)^2-5=0$  ( Square of a negative number is always positive,i.e, -1 × -1 = 1)

⇒ $x^2-5$ = 1 - 5 = - 4  

on subtracting the numbers we get the answer and the answer is negative because a smaller number is subtracted from a larger number.

∴ The value of  $x^2-5=-4$