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:
True, False, True, False, False
Step-by-step explanation:
Answer:
Y =4X -3
Step-by-step explanation:
x1 y1 x2 y2
1 1 -2 -11
(Y2-Y1) (-11)-(1)= -12 ΔY -12
(X2-X1) (-2)-(1)= -3 ΔX -3
slope= 4
B= -3
Y =4X -3
Answer:
(9 + 11) /(5 + 4 + 1)(9 + 11)
20/10(20)
20/200
1/10
I did x - 10 =290
+10 +10
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x = 300 so they took $1.00 a day
