Question

For what values of x, the expression x2 - 4x - 12 is negative?​

Answer 1

Step-by-step explanation:

15+4x−3x

2

<0

⇒15+9x−5x−3x

2

<0

⇒3(5+3x)−x(5+3x)<0

⇒(5+3x)(3−x)<0

⇒(x−3)(3x+5)>0, multiply both sides by −1 , sign will change

⇒x∈(−∞,−

3

5

)∪(3,∞), use wavy curve method