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: P 2: d 3:a
Step-by-step explanation:
A decimal is "." this symbol is used to separate whole numbers from a number value that is less than 1. Decimals basically puts things in its correct "place" according to the place value chart. | Example : $ 1.70 ; Without the decimal point this would be 170$ and in reality it is only one dollar and seventy cents. |
13) 1/6
The truck question) A truck that is green and a truck that is purple
The final question) 1/3
4 sqrt(400) / 4 sqrt(5)
sqrt(400) =20
4 *20
--------
4 sqrt(5)
the 4's on the top and bottom cancel
20
--------
sqrt(5)
I was taught never to leave a sqrt in the denominator
so you need to multiply by sqrt (5) in the numerator and the denominator
20* sqrt(5)
--------
sqrt(5)* sqrt(5)
20* sqrt(5)
--------
5
= 4 sqrt(5)
