Question

`3x²-9x-12`?​

Show ur solution ty~

Answer 1

x = 4, x = -1

Explanation:

I presume that you are solving for the quadratic equation

`3x^2 -9x -12 =0`

We can use the quadratic formula for solving but in this simple equation it is easier to solve by factoring

First divide both sides by 3. This gives

`(3x^2-9x-12)/(3) = x^2 - 3x - 4 = 0`

We can rewrite this as

`x^2 - 4x + 1x - 4 = 0`

Rearranging terms,

`x(x-4) + 1(x-4) = 0`

Factoring out
`(x+4)` we get

`(x-4)(x+1) = 0`

So either (x-4) = 0 which gives x=4

or

(x+1) = 0 which gives x = -1

If you simply wanted to factor the original expression and not solve it then it would be

3(x-4)(x+1)

Let me know if that works

Answer 2

`\tt 3(x - 4)(x + 1)`

Explanation:

`\longrightarrow \sf 3 {x}^(2) - 9x - 12 \\ \\ \sf \longrightarrow 3 {x}^(2) - 12x + 3x - 12 \\ \\ \sf \longrightarrow 3x(x - 4) + 3(x - 4) \\ \\ \sf \longrightarrow (x - 4)(3x + 3) \\ \\ {\boxed {\longrightarrow{ \sf {3(x - 4)(x + 1)} }}}`