I’m pretty sure it’s h because the lines meet in the x axis
X is your number
double it means 2 times x or 2x
add 4
2x+4
subtract my number
2x+4-x=x+4
subtract 3
x+4-3=x+1
the result is x+1 or your number plus 1
Hello!
You can multiply (x-12) and (x+4)
x * x = x^2
x * 4 = 4x
-12 * x = -12x
-12 * 4 = -48
Now we have
x^2 - 8x - 48 = 9
Subtract 9 from both sides
x^2 - 8x -57 = 0
Use the quadratic formula
This give use the answer of
x = 4 +

Hope this helps!
No! it’s a trinomial, a polynomial consists of 4 or more terms :)