Question

find the value of 3(xsquare-2)+4x-8 when x =-2​

Answer 1

Given:

The expression -

$\bf :\longmapsto \: 3( x^2 - 2) + 4x - 8$

The value of x -

$\bf :\longmapsto \: x = -2$

What To Find:

We have to -

• Find the value of the expression.

How To Find:

To find it, we have to -

• First, simplify the expression if possible
• Next, substitute the value of x.
• Then, solve the expression.
• Finally, find the value of the expression.

Solution:

$\sf \longmapsto \: 3( x^2 - 2) + 4x - 8$

Remove the brackets,

$\sf \longmapsto \: 3x^2 - 6 + 4x - 8$

Rearrange the like terms,

$\sf \longmapsto \: 3x^2 + 4x - 8 - 6$

Solve the like terms,

$\sf \longmapsto \: 3x^2 + 4x - 14$

Substitute the value of x i.e -2,

$\sf \longmapsto \: 3(-2^2) + 4(-2) - 14$

Find the square of -2 i.e 4,

$\sf \longmapsto \: 3(4) + 4(-2) - 14$

Multiply 4 by 3,

$\sf \longmapsto \: 12 + 4(-2) - 14$

Multiply 4 by -2,

$\sf \longmapsto \: 12 + (-8) - 14$

Remove the brackets,

$\sf \longmapsto \: 12 - 8 - 14$

First, subtract 8 from 12,

$\sf \longmapsto \: 4 - 14$

Next, subtract 14 from 4,

$\sf \longmapsto \: - 10$

Final Answer:

∴ Thus, the value of the expression is -10.