Start by looking at the vertex form of a quadratic function, f(x) = a(x - h)^2 + k. The variables h and k are the values of the vertex. Plug those in to get f(x) = a(x - 4)^2 + 5. To find the variable a, plug in the point given for the x and y values. So, you get (21) = a((8) - 4)^2 + 5. Solve for a algebraically, and you get a = 1. Finally, plug everything in and simplify the equation. You should get that the quadratic function is f(x) = x^2 - 8x + 21. Hope this helps!
Answer:
x=6.5
y= -.5
Step-by-step explanation:
Plug it in and see if it works to make sure. Good luck
Hey don't cry . I'm not good at math either but try to take a deep breath.
Answer:
-12
Step-by-step explanation:
<u>Step 1: Substitute</u>
ab -> -4 for a and 3 for b
(-4) * (3)
<em>-12</em>
Answer: -12