X2 + 7x +12 > 0 graph from -3 to 3

Question

can you please help me with it :(?? 

 

Answer 1

Czarina, I hope I can still help!

 

If we plug -3 into our equation, (-3)² + 7(-3) + 12 = 9 - 21 + 12 = 0

 

If we plug 3 into our equation, 3² + 7(3) + 12 = 9 + 21 + 12 = 42

 

Now, since f(-3) = 0 and 0 is not greater than 0, we put a circle at (-3,0).

 

Since f(3) = 42, which is greater than 0, we put a point at (3,42).

 

Now, draw a curve attaching the two points.

 

If you really want to be exact, then f(0) = 0² + 7(0) + 12 = 0 + 0 + 12 = 12, so our curve should cross the y-axis at 12.  You can also find f(-2), f(-1), f(1) and f(2), depending on how exact you want the curve to be.

 

Hope this helps!