Sign In
Identify the coordinates of the vertex.
y=0.25(x+4)^2+3
We want to write the equation of the given parabola. To do so, let's recall the vertex form of a quadratic function.
y=a(x-h)^2+k
In this expression, a, h, and k are either positive or negative constants. Let's start by identifying the vertex.
The vertex of this parabola has coordinates (- 4,3). This means that we have h=- 4 and k=3. We can use these values to partially write our function. y=a(x-(- 4))^2+3 ⇕ y=a(x+4)^2+3 We can see in the graph that the parabola opens upwards. Thus, a will be a positive number. To find its value, we will use the given point that is not the vertex.
We can see above that the point has coordinates (- 8,7). Since this point is on the curve, it satisfies its equation. Hence, to find the value of a, we can substitute - 8 for x and 7 for y and simplify.
x= - 8, y= 7
Add terms
Calculate power
LHS-3=RHS-3
.LHS /16.=.RHS /16.
a/b=.a /4./.b /4.
Rearrange equation
Write as a decimal
We found that a=0.25. Now we can complete the equation of the curve. y=0.25(x+4)^2+3