Here i how I would do it:<span>f(x)=−<span>x2</span>+8x+15</span>
set f(x) = 0 to find the points at which the graph crosses the x-axis. So<span>−<span>x2</span>+8x+15=0</span>
multiply through by -1<span><span>x2</span>−8x−15=0</span>
<span>(x−4<span>)2</span>−31=0</span>
<span>x=4±<span>31<span>−−</span>√</span></span>
So these are the points at which the graph crosses the x-axis. To find the point where it crosses the y-axis, set x=0 in your original equation to get 15. Now because of the negative on the x^2, your graph will be an upside down parabola, going through<span>(0,15),(4−<span>31<span>−−</span>√</span>,0)and(4+<span>31<span>−−</span>√</span>,0)</span>
To find the coordinates of the maximum (it is maximum) of the graph, you take a look at the completed square method above. Since we multiplied through by -1, we need to multiply through by it again to get:<span>f(x)=31−(x−4<span>)2</span></span><span>
Now this is maximal when x=4, because x=4 causes -(x-4)^2 to vanish. So the coordinates of the maximum are (4,y). To find the y, simply substitute x=4 into the equation f(x) to give y = 31. So it agrees with the mighty Satellite: (4,31) is the vertex.</span>
Answer:
1. 15 (A)
2. 12 (G)
Step-by-step explanation:
1. We can make an equation out of this...
3x+3=48
x is the age of Geoff which is what we are trying to find out
We have to add 3 to both sides of the equation
3x+3=48
-3 -3
________
we end up with 3x=45
we then have to divide 3 by both sides because its the opposite of
multipling
3x=45
_____
3
we get x=15
2. We can write a problem statement
(2 x 9)-6=?
multiply 2 and 9 <u>FIRST</u>
18-6=?
your answer is 12
Your Welcome! Have a great rest of your day! :)
Answer:
Step-by-step explanation:
y2-y1/x2-x1
-1-(-4)/3-7
3/-4
y=mx+b
For the y coordinate it can be either -4,or -1
-4=3/-4x+b
b=13/4
X= 45
so 2x -> 2(45) would be 90
Answer:
b=10
Step-by-step explanation:
All you have to do is count how many cubes there are.
