Answer:
3. (x + 6)(x + 3)
4. (x-6)(x+2)
Step-by-step explanation:
3. x^2 + 9x + 18
To check if it is factorable, first check the discriminant
b^2 - 4ac
9^2 - 4(1)(18)
81 - 72
9
Since D > 0, there are real number solutions
Now let us try and factor
Find a number that adds to 9 and multiplies to 18
3 and 6 work
Rewrite the equation as
x^2 + 3x + 6x + 18
x(x + 3) + 6(x + 3)
(x + 6)(x + 3)
4. x^2 - 4x - 12
To check if it is factorable, first check the discriminant
b^2 - 4ac
(-4)^2 - 4(1)(-12)
16 + 48 = 64
Since D > 0, there are real number solutions
Now let us try and factor
Find a number that adds to -4 and multiplies to -12
-6 and 2 work
Rewrite the equation as
x^2 - 6x + 2x - 12
x(x - 6) + 2(x - 6)
(x + 2)(x - 6)
